sqlite3.h
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     1 /*
       
     2 ** 2001 September 15
       
     3 **
       
     4 ** The author disclaims copyright to this source code.  In place of
       
     5 ** a legal notice, here is a blessing:
       
     6 **
       
     7 **    May you do good and not evil.
       
     8 **    May you find forgiveness for yourself and forgive others.
       
     9 **    May you share freely, never taking more than you give.
       
    10 **
       
    11 *************************************************************************
       
    12 ** This header file defines the interface that the SQLite library
       
    13 ** presents to client programs.  If a C-function, structure, datatype,
       
    14 ** or constant definition does not appear in this file, then it is
       
    15 ** not a published API of SQLite, is subject to change without
       
    16 ** notice, and should not be referenced by programs that use SQLite.
       
    17 **
       
    18 ** Some of the definitions that are in this file are marked as
       
    19 ** "experimental".  Experimental interfaces are normally new
       
    20 ** features recently added to SQLite.  We do not anticipate changes
       
    21 ** to experimental interfaces but reserve the right to make minor changes
       
    22 ** if experience from use "in the wild" suggest such changes are prudent.
       
    23 **
       
    24 ** The official C-language API documentation for SQLite is derived
       
    25 ** from comments in this file.  This file is the authoritative source
       
    26 ** on how SQLite interfaces are suppose to operate.
       
    27 **
       
    28 ** The name of this file under configuration management is "sqlite.h.in".
       
    29 ** The makefile makes some minor changes to this file (such as inserting
       
    30 ** the version number) and changes its name to "sqlite3.h" as
       
    31 ** part of the build process.
       
    32 */
       
    33 #ifndef _SQLITE3_H_
       
    34 #define _SQLITE3_H_
       
    35 #include <stdarg.h>     /* Needed for the definition of va_list */
       
    36 
       
    37 /*
       
    38 ** Make sure we can call this stuff from C++.
       
    39 */
       
    40 #ifdef __cplusplus
       
    41 extern "C" {
       
    42 #endif
       
    43 
       
    44 
       
    45 /*
       
    46 ** Add the ability to override 'extern'
       
    47 */
       
    48 #ifndef SQLITE_EXTERN
       
    49 # define SQLITE_EXTERN extern
       
    50 #endif
       
    51 
       
    52 #ifndef SQLITE_API
       
    53 # define SQLITE_API
       
    54 #endif
       
    55 
       
    56 
       
    57 /*
       
    58 ** These no-op macros are used in front of interfaces to mark those
       
    59 ** interfaces as either deprecated or experimental.  New applications
       
    60 ** should not use deprecated interfaces - they are support for backwards
       
    61 ** compatibility only.  Application writers should be aware that
       
    62 ** experimental interfaces are subject to change in point releases.
       
    63 **
       
    64 ** These macros used to resolve to various kinds of compiler magic that
       
    65 ** would generate warning messages when they were used.  But that
       
    66 ** compiler magic ended up generating such a flurry of bug reports
       
    67 ** that we have taken it all out and gone back to using simple
       
    68 ** noop macros.
       
    69 */
       
    70 #define SQLITE_DEPRECATED
       
    71 #define SQLITE_EXPERIMENTAL
       
    72 
       
    73 /*
       
    74 ** Ensure these symbols were not defined by some previous header file.
       
    75 */
       
    76 #ifdef SQLITE_VERSION
       
    77 # undef SQLITE_VERSION
       
    78 #endif
       
    79 #ifdef SQLITE_VERSION_NUMBER
       
    80 # undef SQLITE_VERSION_NUMBER
       
    81 #endif
       
    82 
       
    83 /*
       
    84 ** CAPI3REF: Compile-Time Library Version Numbers
       
    85 **
       
    86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
       
    87 ** evaluates to a string literal that is the SQLite version in the
       
    88 ** format "X.Y.Z" where X is the major version number (always 3 for
       
    89 ** SQLite3) and Y is the minor version number and Z is the release number.)^
       
    90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
       
    91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
       
    92 ** numbers used in [SQLITE_VERSION].)^
       
    93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
       
    94 ** be larger than the release from which it is derived.  Either Y will
       
    95 ** be held constant and Z will be incremented or else Y will be incremented
       
    96 ** and Z will be reset to zero.
       
    97 **
       
    98 ** Since version 3.6.18, SQLite source code has been stored in the
       
    99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
       
   100 ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
       
   101 ** a string which identifies a particular check-in of SQLite
       
   102 ** within its configuration management system.  ^The SQLITE_SOURCE_ID
       
   103 ** string contains the date and time of the check-in (UTC) and an SHA1
       
   104 ** hash of the entire source tree.
       
   105 **
       
   106 ** See also: [sqlite3_libversion()],
       
   107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
       
   108 ** [sqlite_version()] and [sqlite_source_id()].
       
   109 */
       
   110 #define SQLITE_VERSION        "3.7.8"
       
   111 #define SQLITE_VERSION_NUMBER 3007008
       
   112 #define SQLITE_SOURCE_ID      "2011-09-19 14:49:19 3e0da808d2f5b4d12046e05980ca04578f581177"
       
   113 
       
   114 /*
       
   115 ** CAPI3REF: Run-Time Library Version Numbers
       
   116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
       
   117 **
       
   118 ** These interfaces provide the same information as the [SQLITE_VERSION],
       
   119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
       
   120 ** but are associated with the library instead of the header file.  ^(Cautious
       
   121 ** programmers might include assert() statements in their application to
       
   122 ** verify that values returned by these interfaces match the macros in
       
   123 ** the header, and thus insure that the application is
       
   124 ** compiled with matching library and header files.
       
   125 **
       
   126 ** <blockquote><pre>
       
   127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
       
   128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
       
   129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
       
   130 ** </pre></blockquote>)^
       
   131 **
       
   132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
       
   133 ** macro.  ^The sqlite3_libversion() function returns a pointer to the
       
   134 ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
       
   135 ** function is provided for use in DLLs since DLL users usually do not have
       
   136 ** direct access to string constants within the DLL.  ^The
       
   137 ** sqlite3_libversion_number() function returns an integer equal to
       
   138 ** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns 
       
   139 ** a pointer to a string constant whose value is the same as the 
       
   140 ** [SQLITE_SOURCE_ID] C preprocessor macro.
       
   141 **
       
   142 ** See also: [sqlite_version()] and [sqlite_source_id()].
       
   143 */
       
   144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
       
   145 SQLITE_API const char *sqlite3_libversion(void);
       
   146 SQLITE_API const char *sqlite3_sourceid(void);
       
   147 SQLITE_API int sqlite3_libversion_number(void);
       
   148 
       
   149 /*
       
   150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
       
   151 **
       
   152 ** ^The sqlite3_compileoption_used() function returns 0 or 1 
       
   153 ** indicating whether the specified option was defined at 
       
   154 ** compile time.  ^The SQLITE_ prefix may be omitted from the 
       
   155 ** option name passed to sqlite3_compileoption_used().  
       
   156 **
       
   157 ** ^The sqlite3_compileoption_get() function allows iterating
       
   158 ** over the list of options that were defined at compile time by
       
   159 ** returning the N-th compile time option string.  ^If N is out of range,
       
   160 ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_ 
       
   161 ** prefix is omitted from any strings returned by 
       
   162 ** sqlite3_compileoption_get().
       
   163 **
       
   164 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
       
   165 ** and sqlite3_compileoption_get() may be omitted by specifying the 
       
   166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
       
   167 **
       
   168 ** See also: SQL functions [sqlite_compileoption_used()] and
       
   169 ** [sqlite_compileoption_get()] and the [compile_options pragma].
       
   170 */
       
   171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
       
   172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
       
   173 SQLITE_API const char *sqlite3_compileoption_get(int N);
       
   174 #endif
       
   175 
       
   176 /*
       
   177 ** CAPI3REF: Test To See If The Library Is Threadsafe
       
   178 **
       
   179 ** ^The sqlite3_threadsafe() function returns zero if and only if
       
   180 ** SQLite was compiled mutexing code omitted due to the
       
   181 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
       
   182 **
       
   183 ** SQLite can be compiled with or without mutexes.  When
       
   184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
       
   185 ** are enabled and SQLite is threadsafe.  When the
       
   186 ** [SQLITE_THREADSAFE] macro is 0, 
       
   187 ** the mutexes are omitted.  Without the mutexes, it is not safe
       
   188 ** to use SQLite concurrently from more than one thread.
       
   189 **
       
   190 ** Enabling mutexes incurs a measurable performance penalty.
       
   191 ** So if speed is of utmost importance, it makes sense to disable
       
   192 ** the mutexes.  But for maximum safety, mutexes should be enabled.
       
   193 ** ^The default behavior is for mutexes to be enabled.
       
   194 **
       
   195 ** This interface can be used by an application to make sure that the
       
   196 ** version of SQLite that it is linking against was compiled with
       
   197 ** the desired setting of the [SQLITE_THREADSAFE] macro.
       
   198 **
       
   199 ** This interface only reports on the compile-time mutex setting
       
   200 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
       
   201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
       
   202 ** can be fully or partially disabled using a call to [sqlite3_config()]
       
   203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
       
   204 ** or [SQLITE_CONFIG_MUTEX].  ^(The return value of the
       
   205 ** sqlite3_threadsafe() function shows only the compile-time setting of
       
   206 ** thread safety, not any run-time changes to that setting made by
       
   207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
       
   208 ** is unchanged by calls to sqlite3_config().)^
       
   209 **
       
   210 ** See the [threading mode] documentation for additional information.
       
   211 */
       
   212 SQLITE_API int sqlite3_threadsafe(void);
       
   213 
       
   214 /*
       
   215 ** CAPI3REF: Database Connection Handle
       
   216 ** KEYWORDS: {database connection} {database connections}
       
   217 **
       
   218 ** Each open SQLite database is represented by a pointer to an instance of
       
   219 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
       
   220 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
       
   221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
       
   222 ** is its destructor.  There are many other interfaces (such as
       
   223 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
       
   224 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
       
   225 ** sqlite3 object.
       
   226 */
       
   227 typedef struct sqlite3 sqlite3;
       
   228 
       
   229 /*
       
   230 ** CAPI3REF: 64-Bit Integer Types
       
   231 ** KEYWORDS: sqlite_int64 sqlite_uint64
       
   232 **
       
   233 ** Because there is no cross-platform way to specify 64-bit integer types
       
   234 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
       
   235 **
       
   236 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
       
   237 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
       
   238 ** compatibility only.
       
   239 **
       
   240 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
       
   241 ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
       
   242 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 
       
   243 ** between 0 and +18446744073709551615 inclusive.
       
   244 */
       
   245 #ifdef SQLITE_INT64_TYPE
       
   246   typedef SQLITE_INT64_TYPE sqlite_int64;
       
   247   typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
       
   248 #elif defined(_MSC_VER) || defined(__BORLANDC__)
       
   249   typedef __int64 sqlite_int64;
       
   250   typedef unsigned __int64 sqlite_uint64;
       
   251 #else
       
   252   typedef long long int sqlite_int64;
       
   253   typedef unsigned long long int sqlite_uint64;
       
   254 #endif
       
   255 typedef sqlite_int64 sqlite3_int64;
       
   256 typedef sqlite_uint64 sqlite3_uint64;
       
   257 
       
   258 /*
       
   259 ** If compiling for a processor that lacks floating point support,
       
   260 ** substitute integer for floating-point.
       
   261 */
       
   262 #ifdef SQLITE_OMIT_FLOATING_POINT
       
   263 # define double sqlite3_int64
       
   264 #endif
       
   265 
       
   266 /*
       
   267 ** CAPI3REF: Closing A Database Connection
       
   268 **
       
   269 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
       
   270 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
       
   271 ** successfully destroyed and all associated resources are deallocated.
       
   272 **
       
   273 ** Applications must [sqlite3_finalize | finalize] all [prepared statements]
       
   274 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
       
   275 ** the [sqlite3] object prior to attempting to close the object.  ^If
       
   276 ** sqlite3_close() is called on a [database connection] that still has
       
   277 ** outstanding [prepared statements] or [BLOB handles], then it returns
       
   278 ** SQLITE_BUSY.
       
   279 **
       
   280 ** ^If [sqlite3_close()] is invoked while a transaction is open,
       
   281 ** the transaction is automatically rolled back.
       
   282 **
       
   283 ** The C parameter to [sqlite3_close(C)] must be either a NULL
       
   284 ** pointer or an [sqlite3] object pointer obtained
       
   285 ** from [sqlite3_open()], [sqlite3_open16()], or
       
   286 ** [sqlite3_open_v2()], and not previously closed.
       
   287 ** ^Calling sqlite3_close() with a NULL pointer argument is a 
       
   288 ** harmless no-op.
       
   289 */
       
   290 SQLITE_API int sqlite3_close(sqlite3 *);
       
   291 
       
   292 /*
       
   293 ** The type for a callback function.
       
   294 ** This is legacy and deprecated.  It is included for historical
       
   295 ** compatibility and is not documented.
       
   296 */
       
   297 typedef int (*sqlite3_callback)(void*,int,char**, char**);
       
   298 
       
   299 /*
       
   300 ** CAPI3REF: One-Step Query Execution Interface
       
   301 **
       
   302 ** The sqlite3_exec() interface is a convenience wrapper around
       
   303 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
       
   304 ** that allows an application to run multiple statements of SQL
       
   305 ** without having to use a lot of C code. 
       
   306 **
       
   307 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
       
   308 ** semicolon-separate SQL statements passed into its 2nd argument,
       
   309 ** in the context of the [database connection] passed in as its 1st
       
   310 ** argument.  ^If the callback function of the 3rd argument to
       
   311 ** sqlite3_exec() is not NULL, then it is invoked for each result row
       
   312 ** coming out of the evaluated SQL statements.  ^The 4th argument to
       
   313 ** sqlite3_exec() is relayed through to the 1st argument of each
       
   314 ** callback invocation.  ^If the callback pointer to sqlite3_exec()
       
   315 ** is NULL, then no callback is ever invoked and result rows are
       
   316 ** ignored.
       
   317 **
       
   318 ** ^If an error occurs while evaluating the SQL statements passed into
       
   319 ** sqlite3_exec(), then execution of the current statement stops and
       
   320 ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
       
   321 ** is not NULL then any error message is written into memory obtained
       
   322 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
       
   323 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
       
   324 ** on error message strings returned through the 5th parameter of
       
   325 ** of sqlite3_exec() after the error message string is no longer needed.
       
   326 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
       
   327 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
       
   328 ** NULL before returning.
       
   329 **
       
   330 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
       
   331 ** routine returns SQLITE_ABORT without invoking the callback again and
       
   332 ** without running any subsequent SQL statements.
       
   333 **
       
   334 ** ^The 2nd argument to the sqlite3_exec() callback function is the
       
   335 ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
       
   336 ** callback is an array of pointers to strings obtained as if from
       
   337 ** [sqlite3_column_text()], one for each column.  ^If an element of a
       
   338 ** result row is NULL then the corresponding string pointer for the
       
   339 ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
       
   340 ** sqlite3_exec() callback is an array of pointers to strings where each
       
   341 ** entry represents the name of corresponding result column as obtained
       
   342 ** from [sqlite3_column_name()].
       
   343 **
       
   344 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
       
   345 ** to an empty string, or a pointer that contains only whitespace and/or 
       
   346 ** SQL comments, then no SQL statements are evaluated and the database
       
   347 ** is not changed.
       
   348 **
       
   349 ** Restrictions:
       
   350 **
       
   351 ** <ul>
       
   352 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
       
   353 **      is a valid and open [database connection].
       
   354 ** <li> The application must not close [database connection] specified by
       
   355 **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
       
   356 ** <li> The application must not modify the SQL statement text passed into
       
   357 **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
       
   358 ** </ul>
       
   359 */
       
   360 SQLITE_API int sqlite3_exec(
       
   361   sqlite3*,                                  /* An open database */
       
   362   const char *sql,                           /* SQL to be evaluated */
       
   363   int (*callback)(void*,int,char**,char**),  /* Callback function */
       
   364   void *,                                    /* 1st argument to callback */
       
   365   char **errmsg                              /* Error msg written here */
       
   366 );
       
   367 
       
   368 /*
       
   369 ** CAPI3REF: Result Codes
       
   370 ** KEYWORDS: SQLITE_OK {error code} {error codes}
       
   371 ** KEYWORDS: {result code} {result codes}
       
   372 **
       
   373 ** Many SQLite functions return an integer result code from the set shown
       
   374 ** here in order to indicates success or failure.
       
   375 **
       
   376 ** New error codes may be added in future versions of SQLite.
       
   377 **
       
   378 ** See also: [SQLITE_IOERR_READ | extended result codes],
       
   379 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
       
   380 */
       
   381 #define SQLITE_OK           0   /* Successful result */
       
   382 /* beginning-of-error-codes */
       
   383 #define SQLITE_ERROR        1   /* SQL error or missing database */
       
   384 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
       
   385 #define SQLITE_PERM         3   /* Access permission denied */
       
   386 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
       
   387 #define SQLITE_BUSY         5   /* The database file is locked */
       
   388 #define SQLITE_LOCKED       6   /* A table in the database is locked */
       
   389 #define SQLITE_NOMEM        7   /* A malloc() failed */
       
   390 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
       
   391 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
       
   392 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
       
   393 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
       
   394 #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
       
   395 #define SQLITE_FULL        13   /* Insertion failed because database is full */
       
   396 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
       
   397 #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
       
   398 #define SQLITE_EMPTY       16   /* Database is empty */
       
   399 #define SQLITE_SCHEMA      17   /* The database schema changed */
       
   400 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
       
   401 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
       
   402 #define SQLITE_MISMATCH    20   /* Data type mismatch */
       
   403 #define SQLITE_MISUSE      21   /* Library used incorrectly */
       
   404 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
       
   405 #define SQLITE_AUTH        23   /* Authorization denied */
       
   406 #define SQLITE_FORMAT      24   /* Auxiliary database format error */
       
   407 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
       
   408 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
       
   409 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
       
   410 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
       
   411 /* end-of-error-codes */
       
   412 
       
   413 /*
       
   414 ** CAPI3REF: Extended Result Codes
       
   415 ** KEYWORDS: {extended error code} {extended error codes}
       
   416 ** KEYWORDS: {extended result code} {extended result codes}
       
   417 **
       
   418 ** In its default configuration, SQLite API routines return one of 26 integer
       
   419 ** [SQLITE_OK | result codes].  However, experience has shown that many of
       
   420 ** these result codes are too coarse-grained.  They do not provide as
       
   421 ** much information about problems as programmers might like.  In an effort to
       
   422 ** address this, newer versions of SQLite (version 3.3.8 and later) include
       
   423 ** support for additional result codes that provide more detailed information
       
   424 ** about errors. The extended result codes are enabled or disabled
       
   425 ** on a per database connection basis using the
       
   426 ** [sqlite3_extended_result_codes()] API.
       
   427 **
       
   428 ** Some of the available extended result codes are listed here.
       
   429 ** One may expect the number of extended result codes will be expand
       
   430 ** over time.  Software that uses extended result codes should expect
       
   431 ** to see new result codes in future releases of SQLite.
       
   432 **
       
   433 ** The SQLITE_OK result code will never be extended.  It will always
       
   434 ** be exactly zero.
       
   435 */
       
   436 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
       
   437 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
       
   438 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
       
   439 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
       
   440 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
       
   441 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
       
   442 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
       
   443 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
       
   444 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
       
   445 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
       
   446 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
       
   447 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
       
   448 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
       
   449 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
       
   450 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
       
   451 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
       
   452 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
       
   453 #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
       
   454 #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
       
   455 #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
       
   456 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
       
   457 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
       
   458 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
       
   459 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
       
   460 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
       
   461 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
       
   462 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
       
   463 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
       
   464 
       
   465 /*
       
   466 ** CAPI3REF: Flags For File Open Operations
       
   467 **
       
   468 ** These bit values are intended for use in the
       
   469 ** 3rd parameter to the [sqlite3_open_v2()] interface and
       
   470 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
       
   471 */
       
   472 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
       
   473 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
       
   474 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
       
   475 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
       
   476 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
       
   477 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
       
   478 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
       
   479 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
       
   480 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
       
   481 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
       
   482 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
       
   483 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
       
   484 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
       
   485 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
       
   486 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
       
   487 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
       
   488 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
       
   489 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
       
   490 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
       
   491 
       
   492 /* Reserved:                         0x00F00000 */
       
   493 
       
   494 /*
       
   495 ** CAPI3REF: Device Characteristics
       
   496 **
       
   497 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
       
   498 ** object returns an integer which is a vector of the these
       
   499 ** bit values expressing I/O characteristics of the mass storage
       
   500 ** device that holds the file that the [sqlite3_io_methods]
       
   501 ** refers to.
       
   502 **
       
   503 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
       
   504 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
       
   505 ** mean that writes of blocks that are nnn bytes in size and
       
   506 ** are aligned to an address which is an integer multiple of
       
   507 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
       
   508 ** that when data is appended to a file, the data is appended
       
   509 ** first then the size of the file is extended, never the other
       
   510 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
       
   511 ** information is written to disk in the same order as calls
       
   512 ** to xWrite().
       
   513 */
       
   514 #define SQLITE_IOCAP_ATOMIC                 0x00000001
       
   515 #define SQLITE_IOCAP_ATOMIC512              0x00000002
       
   516 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
       
   517 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
       
   518 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
       
   519 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
       
   520 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
       
   521 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
       
   522 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
       
   523 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
       
   524 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
       
   525 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
       
   526 
       
   527 /*
       
   528 ** CAPI3REF: File Locking Levels
       
   529 **
       
   530 ** SQLite uses one of these integer values as the second
       
   531 ** argument to calls it makes to the xLock() and xUnlock() methods
       
   532 ** of an [sqlite3_io_methods] object.
       
   533 */
       
   534 #define SQLITE_LOCK_NONE          0
       
   535 #define SQLITE_LOCK_SHARED        1
       
   536 #define SQLITE_LOCK_RESERVED      2
       
   537 #define SQLITE_LOCK_PENDING       3
       
   538 #define SQLITE_LOCK_EXCLUSIVE     4
       
   539 
       
   540 /*
       
   541 ** CAPI3REF: Synchronization Type Flags
       
   542 **
       
   543 ** When SQLite invokes the xSync() method of an
       
   544 ** [sqlite3_io_methods] object it uses a combination of
       
   545 ** these integer values as the second argument.
       
   546 **
       
   547 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
       
   548 ** sync operation only needs to flush data to mass storage.  Inode
       
   549 ** information need not be flushed. If the lower four bits of the flag
       
   550 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
       
   551 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
       
   552 ** to use Mac OS X style fullsync instead of fsync().
       
   553 **
       
   554 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
       
   555 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
       
   556 ** settings.  The [synchronous pragma] determines when calls to the
       
   557 ** xSync VFS method occur and applies uniformly across all platforms.
       
   558 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
       
   559 ** energetic or rigorous or forceful the sync operations are and
       
   560 ** only make a difference on Mac OSX for the default SQLite code.
       
   561 ** (Third-party VFS implementations might also make the distinction
       
   562 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
       
   563 ** operating systems natively supported by SQLite, only Mac OSX
       
   564 ** cares about the difference.)
       
   565 */
       
   566 #define SQLITE_SYNC_NORMAL        0x00002
       
   567 #define SQLITE_SYNC_FULL          0x00003
       
   568 #define SQLITE_SYNC_DATAONLY      0x00010
       
   569 
       
   570 /*
       
   571 ** CAPI3REF: OS Interface Open File Handle
       
   572 **
       
   573 ** An [sqlite3_file] object represents an open file in the 
       
   574 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
       
   575 ** implementations will
       
   576 ** want to subclass this object by appending additional fields
       
   577 ** for their own use.  The pMethods entry is a pointer to an
       
   578 ** [sqlite3_io_methods] object that defines methods for performing
       
   579 ** I/O operations on the open file.
       
   580 */
       
   581 typedef struct sqlite3_file sqlite3_file;
       
   582 struct sqlite3_file {
       
   583   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
       
   584 };
       
   585 
       
   586 /*
       
   587 ** CAPI3REF: OS Interface File Virtual Methods Object
       
   588 **
       
   589 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
       
   590 ** [sqlite3_file] object (or, more commonly, a subclass of the
       
   591 ** [sqlite3_file] object) with a pointer to an instance of this object.
       
   592 ** This object defines the methods used to perform various operations
       
   593 ** against the open file represented by the [sqlite3_file] object.
       
   594 **
       
   595 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 
       
   596 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
       
   597 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
       
   598 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
       
   599 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
       
   600 ** to NULL.
       
   601 **
       
   602 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
       
   603 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
       
   604 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
       
   605 ** flag may be ORed in to indicate that only the data of the file
       
   606 ** and not its inode needs to be synced.
       
   607 **
       
   608 ** The integer values to xLock() and xUnlock() are one of
       
   609 ** <ul>
       
   610 ** <li> [SQLITE_LOCK_NONE],
       
   611 ** <li> [SQLITE_LOCK_SHARED],
       
   612 ** <li> [SQLITE_LOCK_RESERVED],
       
   613 ** <li> [SQLITE_LOCK_PENDING], or
       
   614 ** <li> [SQLITE_LOCK_EXCLUSIVE].
       
   615 ** </ul>
       
   616 ** xLock() increases the lock. xUnlock() decreases the lock.
       
   617 ** The xCheckReservedLock() method checks whether any database connection,
       
   618 ** either in this process or in some other process, is holding a RESERVED,
       
   619 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
       
   620 ** if such a lock exists and false otherwise.
       
   621 **
       
   622 ** The xFileControl() method is a generic interface that allows custom
       
   623 ** VFS implementations to directly control an open file using the
       
   624 ** [sqlite3_file_control()] interface.  The second "op" argument is an
       
   625 ** integer opcode.  The third argument is a generic pointer intended to
       
   626 ** point to a structure that may contain arguments or space in which to
       
   627 ** write return values.  Potential uses for xFileControl() might be
       
   628 ** functions to enable blocking locks with timeouts, to change the
       
   629 ** locking strategy (for example to use dot-file locks), to inquire
       
   630 ** about the status of a lock, or to break stale locks.  The SQLite
       
   631 ** core reserves all opcodes less than 100 for its own use.
       
   632 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
       
   633 ** Applications that define a custom xFileControl method should use opcodes
       
   634 ** greater than 100 to avoid conflicts.  VFS implementations should
       
   635 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
       
   636 ** recognize.
       
   637 **
       
   638 ** The xSectorSize() method returns the sector size of the
       
   639 ** device that underlies the file.  The sector size is the
       
   640 ** minimum write that can be performed without disturbing
       
   641 ** other bytes in the file.  The xDeviceCharacteristics()
       
   642 ** method returns a bit vector describing behaviors of the
       
   643 ** underlying device:
       
   644 **
       
   645 ** <ul>
       
   646 ** <li> [SQLITE_IOCAP_ATOMIC]
       
   647 ** <li> [SQLITE_IOCAP_ATOMIC512]
       
   648 ** <li> [SQLITE_IOCAP_ATOMIC1K]
       
   649 ** <li> [SQLITE_IOCAP_ATOMIC2K]
       
   650 ** <li> [SQLITE_IOCAP_ATOMIC4K]
       
   651 ** <li> [SQLITE_IOCAP_ATOMIC8K]
       
   652 ** <li> [SQLITE_IOCAP_ATOMIC16K]
       
   653 ** <li> [SQLITE_IOCAP_ATOMIC32K]
       
   654 ** <li> [SQLITE_IOCAP_ATOMIC64K]
       
   655 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
       
   656 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
       
   657 ** </ul>
       
   658 **
       
   659 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
       
   660 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
       
   661 ** mean that writes of blocks that are nnn bytes in size and
       
   662 ** are aligned to an address which is an integer multiple of
       
   663 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
       
   664 ** that when data is appended to a file, the data is appended
       
   665 ** first then the size of the file is extended, never the other
       
   666 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
       
   667 ** information is written to disk in the same order as calls
       
   668 ** to xWrite().
       
   669 **
       
   670 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
       
   671 ** in the unread portions of the buffer with zeros.  A VFS that
       
   672 ** fails to zero-fill short reads might seem to work.  However,
       
   673 ** failure to zero-fill short reads will eventually lead to
       
   674 ** database corruption.
       
   675 */
       
   676 typedef struct sqlite3_io_methods sqlite3_io_methods;
       
   677 struct sqlite3_io_methods {
       
   678   int iVersion;
       
   679   int (*xClose)(sqlite3_file*);
       
   680   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
       
   681   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
       
   682   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
       
   683   int (*xSync)(sqlite3_file*, int flags);
       
   684   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
       
   685   int (*xLock)(sqlite3_file*, int);
       
   686   int (*xUnlock)(sqlite3_file*, int);
       
   687   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
       
   688   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
       
   689   int (*xSectorSize)(sqlite3_file*);
       
   690   int (*xDeviceCharacteristics)(sqlite3_file*);
       
   691   /* Methods above are valid for version 1 */
       
   692   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
       
   693   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
       
   694   void (*xShmBarrier)(sqlite3_file*);
       
   695   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
       
   696   /* Methods above are valid for version 2 */
       
   697   /* Additional methods may be added in future releases */
       
   698 };
       
   699 
       
   700 /*
       
   701 ** CAPI3REF: Standard File Control Opcodes
       
   702 **
       
   703 ** These integer constants are opcodes for the xFileControl method
       
   704 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
       
   705 ** interface.
       
   706 **
       
   707 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
       
   708 ** opcode causes the xFileControl method to write the current state of
       
   709 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
       
   710 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
       
   711 ** into an integer that the pArg argument points to. This capability
       
   712 ** is used during testing and only needs to be supported when SQLITE_TEST
       
   713 ** is defined.
       
   714 **
       
   715 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
       
   716 ** layer a hint of how large the database file will grow to be during the
       
   717 ** current transaction.  This hint is not guaranteed to be accurate but it
       
   718 ** is often close.  The underlying VFS might choose to preallocate database
       
   719 ** file space based on this hint in order to help writes to the database
       
   720 ** file run faster.
       
   721 **
       
   722 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
       
   723 ** extends and truncates the database file in chunks of a size specified
       
   724 ** by the user. The fourth argument to [sqlite3_file_control()] should 
       
   725 ** point to an integer (type int) containing the new chunk-size to use
       
   726 ** for the nominated database. Allocating database file space in large
       
   727 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
       
   728 ** improve performance on some systems.
       
   729 **
       
   730 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
       
   731 ** to the [sqlite3_file] object associated with a particular database
       
   732 ** connection.  See the [sqlite3_file_control()] documentation for
       
   733 ** additional information.
       
   734 **
       
   735 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
       
   736 ** SQLite and sent to all VFSes in place of a call to the xSync method
       
   737 ** when the database connection has [PRAGMA synchronous] set to OFF.)^
       
   738 ** Some specialized VFSes need this signal in order to operate correctly
       
   739 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 
       
   740 ** VFSes do not need this signal and should silently ignore this opcode.
       
   741 ** Applications should not call [sqlite3_file_control()] with this
       
   742 ** opcode as doing so may disrupt the operation of the specialized VFSes
       
   743 ** that do require it.  
       
   744 **
       
   745 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
       
   746 ** retry counts and intervals for certain disk I/O operations for the
       
   747 ** windows [VFS] in order to work to provide robustness against
       
   748 ** anti-virus programs.  By default, the windows VFS will retry file read,
       
   749 ** file write, and file delete opertions up to 10 times, with a delay
       
   750 ** of 25 milliseconds before the first retry and with the delay increasing
       
   751 ** by an additional 25 milliseconds with each subsequent retry.  This
       
   752 ** opcode allows those to values (10 retries and 25 milliseconds of delay)
       
   753 ** to be adjusted.  The values are changed for all database connections
       
   754 ** within the same process.  The argument is a pointer to an array of two
       
   755 ** integers where the first integer i the new retry count and the second
       
   756 ** integer is the delay.  If either integer is negative, then the setting
       
   757 ** is not changed but instead the prior value of that setting is written
       
   758 ** into the array entry, allowing the current retry settings to be
       
   759 ** interrogated.  The zDbName parameter is ignored.
       
   760 **
       
   761 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
       
   762 ** persistent [WAL | Write AHead Log] setting.  By default, the auxiliary
       
   763 ** write ahead log and shared memory files used for transaction control
       
   764 ** are automatically deleted when the latest connection to the database
       
   765 ** closes.  Setting persistent WAL mode causes those files to persist after
       
   766 ** close.  Persisting the files is useful when other processes that do not
       
   767 ** have write permission on the directory containing the database file want
       
   768 ** to read the database file, as the WAL and shared memory files must exist
       
   769 ** in order for the database to be readable.  The fourth parameter to
       
   770 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
       
   771 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
       
   772 ** WAL mode.  If the integer is -1, then it is overwritten with the current
       
   773 ** WAL persistence setting.
       
   774 ** 
       
   775 */
       
   776 #define SQLITE_FCNTL_LOCKSTATE        1
       
   777 #define SQLITE_GET_LOCKPROXYFILE      2
       
   778 #define SQLITE_SET_LOCKPROXYFILE      3
       
   779 #define SQLITE_LAST_ERRNO             4
       
   780 #define SQLITE_FCNTL_SIZE_HINT        5
       
   781 #define SQLITE_FCNTL_CHUNK_SIZE       6
       
   782 #define SQLITE_FCNTL_FILE_POINTER     7
       
   783 #define SQLITE_FCNTL_SYNC_OMITTED     8
       
   784 #define SQLITE_FCNTL_WIN32_AV_RETRY   9
       
   785 #define SQLITE_FCNTL_PERSIST_WAL     10
       
   786 
       
   787 /*
       
   788 ** CAPI3REF: Mutex Handle
       
   789 **
       
   790 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
       
   791 ** abstract type for a mutex object.  The SQLite core never looks
       
   792 ** at the internal representation of an [sqlite3_mutex].  It only
       
   793 ** deals with pointers to the [sqlite3_mutex] object.
       
   794 **
       
   795 ** Mutexes are created using [sqlite3_mutex_alloc()].
       
   796 */
       
   797 typedef struct sqlite3_mutex sqlite3_mutex;
       
   798 
       
   799 /*
       
   800 ** CAPI3REF: OS Interface Object
       
   801 **
       
   802 ** An instance of the sqlite3_vfs object defines the interface between
       
   803 ** the SQLite core and the underlying operating system.  The "vfs"
       
   804 ** in the name of the object stands for "virtual file system".  See
       
   805 ** the [VFS | VFS documentation] for further information.
       
   806 **
       
   807 ** The value of the iVersion field is initially 1 but may be larger in
       
   808 ** future versions of SQLite.  Additional fields may be appended to this
       
   809 ** object when the iVersion value is increased.  Note that the structure
       
   810 ** of the sqlite3_vfs object changes in the transaction between
       
   811 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
       
   812 ** modified.
       
   813 **
       
   814 ** The szOsFile field is the size of the subclassed [sqlite3_file]
       
   815 ** structure used by this VFS.  mxPathname is the maximum length of
       
   816 ** a pathname in this VFS.
       
   817 **
       
   818 ** Registered sqlite3_vfs objects are kept on a linked list formed by
       
   819 ** the pNext pointer.  The [sqlite3_vfs_register()]
       
   820 ** and [sqlite3_vfs_unregister()] interfaces manage this list
       
   821 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
       
   822 ** searches the list.  Neither the application code nor the VFS
       
   823 ** implementation should use the pNext pointer.
       
   824 **
       
   825 ** The pNext field is the only field in the sqlite3_vfs
       
   826 ** structure that SQLite will ever modify.  SQLite will only access
       
   827 ** or modify this field while holding a particular static mutex.
       
   828 ** The application should never modify anything within the sqlite3_vfs
       
   829 ** object once the object has been registered.
       
   830 **
       
   831 ** The zName field holds the name of the VFS module.  The name must
       
   832 ** be unique across all VFS modules.
       
   833 **
       
   834 ** [[sqlite3_vfs.xOpen]]
       
   835 ** ^SQLite guarantees that the zFilename parameter to xOpen
       
   836 ** is either a NULL pointer or string obtained
       
   837 ** from xFullPathname() with an optional suffix added.
       
   838 ** ^If a suffix is added to the zFilename parameter, it will
       
   839 ** consist of a single "-" character followed by no more than
       
   840 ** 10 alphanumeric and/or "-" characters.
       
   841 ** ^SQLite further guarantees that
       
   842 ** the string will be valid and unchanged until xClose() is
       
   843 ** called. Because of the previous sentence,
       
   844 ** the [sqlite3_file] can safely store a pointer to the
       
   845 ** filename if it needs to remember the filename for some reason.
       
   846 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
       
   847 ** must invent its own temporary name for the file.  ^Whenever the 
       
   848 ** xFilename parameter is NULL it will also be the case that the
       
   849 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
       
   850 **
       
   851 ** The flags argument to xOpen() includes all bits set in
       
   852 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
       
   853 ** or [sqlite3_open16()] is used, then flags includes at least
       
   854 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 
       
   855 ** If xOpen() opens a file read-only then it sets *pOutFlags to
       
   856 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
       
   857 **
       
   858 ** ^(SQLite will also add one of the following flags to the xOpen()
       
   859 ** call, depending on the object being opened:
       
   860 **
       
   861 ** <ul>
       
   862 ** <li>  [SQLITE_OPEN_MAIN_DB]
       
   863 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
       
   864 ** <li>  [SQLITE_OPEN_TEMP_DB]
       
   865 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
       
   866 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
       
   867 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
       
   868 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
       
   869 ** <li>  [SQLITE_OPEN_WAL]
       
   870 ** </ul>)^
       
   871 **
       
   872 ** The file I/O implementation can use the object type flags to
       
   873 ** change the way it deals with files.  For example, an application
       
   874 ** that does not care about crash recovery or rollback might make
       
   875 ** the open of a journal file a no-op.  Writes to this journal would
       
   876 ** also be no-ops, and any attempt to read the journal would return
       
   877 ** SQLITE_IOERR.  Or the implementation might recognize that a database
       
   878 ** file will be doing page-aligned sector reads and writes in a random
       
   879 ** order and set up its I/O subsystem accordingly.
       
   880 **
       
   881 ** SQLite might also add one of the following flags to the xOpen method:
       
   882 **
       
   883 ** <ul>
       
   884 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
       
   885 ** <li> [SQLITE_OPEN_EXCLUSIVE]
       
   886 ** </ul>
       
   887 **
       
   888 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
       
   889 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
       
   890 ** will be set for TEMP databases and their journals, transient
       
   891 ** databases, and subjournals.
       
   892 **
       
   893 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
       
   894 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
       
   895 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
       
   896 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 
       
   897 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
       
   898 ** be created, and that it is an error if it already exists.
       
   899 ** It is <i>not</i> used to indicate the file should be opened 
       
   900 ** for exclusive access.
       
   901 **
       
   902 ** ^At least szOsFile bytes of memory are allocated by SQLite
       
   903 ** to hold the  [sqlite3_file] structure passed as the third
       
   904 ** argument to xOpen.  The xOpen method does not have to
       
   905 ** allocate the structure; it should just fill it in.  Note that
       
   906 ** the xOpen method must set the sqlite3_file.pMethods to either
       
   907 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
       
   908 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
       
   909 ** element will be valid after xOpen returns regardless of the success
       
   910 ** or failure of the xOpen call.
       
   911 **
       
   912 ** [[sqlite3_vfs.xAccess]]
       
   913 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
       
   914 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
       
   915 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
       
   916 ** to test whether a file is at least readable.   The file can be a
       
   917 ** directory.
       
   918 **
       
   919 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
       
   920 ** output buffer xFullPathname.  The exact size of the output buffer
       
   921 ** is also passed as a parameter to both  methods. If the output buffer
       
   922 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
       
   923 ** handled as a fatal error by SQLite, vfs implementations should endeavor
       
   924 ** to prevent this by setting mxPathname to a sufficiently large value.
       
   925 **
       
   926 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
       
   927 ** interfaces are not strictly a part of the filesystem, but they are
       
   928 ** included in the VFS structure for completeness.
       
   929 ** The xRandomness() function attempts to return nBytes bytes
       
   930 ** of good-quality randomness into zOut.  The return value is
       
   931 ** the actual number of bytes of randomness obtained.
       
   932 ** The xSleep() method causes the calling thread to sleep for at
       
   933 ** least the number of microseconds given.  ^The xCurrentTime()
       
   934 ** method returns a Julian Day Number for the current date and time as
       
   935 ** a floating point value.
       
   936 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
       
   937 ** Day Number multiplied by 86400000 (the number of milliseconds in 
       
   938 ** a 24-hour day).  
       
   939 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
       
   940 ** date and time if that method is available (if iVersion is 2 or 
       
   941 ** greater and the function pointer is not NULL) and will fall back
       
   942 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
       
   943 **
       
   944 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
       
   945 ** are not used by the SQLite core.  These optional interfaces are provided
       
   946 ** by some VFSes to facilitate testing of the VFS code. By overriding 
       
   947 ** system calls with functions under its control, a test program can
       
   948 ** simulate faults and error conditions that would otherwise be difficult
       
   949 ** or impossible to induce.  The set of system calls that can be overridden
       
   950 ** varies from one VFS to another, and from one version of the same VFS to the
       
   951 ** next.  Applications that use these interfaces must be prepared for any
       
   952 ** or all of these interfaces to be NULL or for their behavior to change
       
   953 ** from one release to the next.  Applications must not attempt to access
       
   954 ** any of these methods if the iVersion of the VFS is less than 3.
       
   955 */
       
   956 typedef struct sqlite3_vfs sqlite3_vfs;
       
   957 typedef void (*sqlite3_syscall_ptr)(void);
       
   958 struct sqlite3_vfs {
       
   959   int iVersion;            /* Structure version number (currently 3) */
       
   960   int szOsFile;            /* Size of subclassed sqlite3_file */
       
   961   int mxPathname;          /* Maximum file pathname length */
       
   962   sqlite3_vfs *pNext;      /* Next registered VFS */
       
   963   const char *zName;       /* Name of this virtual file system */
       
   964   void *pAppData;          /* Pointer to application-specific data */
       
   965   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
       
   966                int flags, int *pOutFlags);
       
   967   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
       
   968   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
       
   969   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
       
   970   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
       
   971   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
       
   972   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
       
   973   void (*xDlClose)(sqlite3_vfs*, void*);
       
   974   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
       
   975   int (*xSleep)(sqlite3_vfs*, int microseconds);
       
   976   int (*xCurrentTime)(sqlite3_vfs*, double*);
       
   977   int (*xGetLastError)(sqlite3_vfs*, int, char *);
       
   978   /*
       
   979   ** The methods above are in version 1 of the sqlite_vfs object
       
   980   ** definition.  Those that follow are added in version 2 or later
       
   981   */
       
   982   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
       
   983   /*
       
   984   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
       
   985   ** Those below are for version 3 and greater.
       
   986   */
       
   987   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
       
   988   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
       
   989   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
       
   990   /*
       
   991   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
       
   992   ** New fields may be appended in figure versions.  The iVersion
       
   993   ** value will increment whenever this happens. 
       
   994   */
       
   995 };
       
   996 
       
   997 /*
       
   998 ** CAPI3REF: Flags for the xAccess VFS method
       
   999 **
       
  1000 ** These integer constants can be used as the third parameter to
       
  1001 ** the xAccess method of an [sqlite3_vfs] object.  They determine
       
  1002 ** what kind of permissions the xAccess method is looking for.
       
  1003 ** With SQLITE_ACCESS_EXISTS, the xAccess method
       
  1004 ** simply checks whether the file exists.
       
  1005 ** With SQLITE_ACCESS_READWRITE, the xAccess method
       
  1006 ** checks whether the named directory is both readable and writable
       
  1007 ** (in other words, if files can be added, removed, and renamed within
       
  1008 ** the directory).
       
  1009 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
       
  1010 ** [temp_store_directory pragma], though this could change in a future
       
  1011 ** release of SQLite.
       
  1012 ** With SQLITE_ACCESS_READ, the xAccess method
       
  1013 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
       
  1014 ** currently unused, though it might be used in a future release of
       
  1015 ** SQLite.
       
  1016 */
       
  1017 #define SQLITE_ACCESS_EXISTS    0
       
  1018 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
       
  1019 #define SQLITE_ACCESS_READ      2   /* Unused */
       
  1020 
       
  1021 /*
       
  1022 ** CAPI3REF: Flags for the xShmLock VFS method
       
  1023 **
       
  1024 ** These integer constants define the various locking operations
       
  1025 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
       
  1026 ** following are the only legal combinations of flags to the
       
  1027 ** xShmLock method:
       
  1028 **
       
  1029 ** <ul>
       
  1030 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
       
  1031 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
       
  1032 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
       
  1033 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
       
  1034 ** </ul>
       
  1035 **
       
  1036 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
       
  1037 ** was given no the corresponding lock.  
       
  1038 **
       
  1039 ** The xShmLock method can transition between unlocked and SHARED or
       
  1040 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
       
  1041 ** and EXCLUSIVE.
       
  1042 */
       
  1043 #define SQLITE_SHM_UNLOCK       1
       
  1044 #define SQLITE_SHM_LOCK         2
       
  1045 #define SQLITE_SHM_SHARED       4
       
  1046 #define SQLITE_SHM_EXCLUSIVE    8
       
  1047 
       
  1048 /*
       
  1049 ** CAPI3REF: Maximum xShmLock index
       
  1050 **
       
  1051 ** The xShmLock method on [sqlite3_io_methods] may use values
       
  1052 ** between 0 and this upper bound as its "offset" argument.
       
  1053 ** The SQLite core will never attempt to acquire or release a
       
  1054 ** lock outside of this range
       
  1055 */
       
  1056 #define SQLITE_SHM_NLOCK        8
       
  1057 
       
  1058 
       
  1059 /*
       
  1060 ** CAPI3REF: Initialize The SQLite Library
       
  1061 **
       
  1062 ** ^The sqlite3_initialize() routine initializes the
       
  1063 ** SQLite library.  ^The sqlite3_shutdown() routine
       
  1064 ** deallocates any resources that were allocated by sqlite3_initialize().
       
  1065 ** These routines are designed to aid in process initialization and
       
  1066 ** shutdown on embedded systems.  Workstation applications using
       
  1067 ** SQLite normally do not need to invoke either of these routines.
       
  1068 **
       
  1069 ** A call to sqlite3_initialize() is an "effective" call if it is
       
  1070 ** the first time sqlite3_initialize() is invoked during the lifetime of
       
  1071 ** the process, or if it is the first time sqlite3_initialize() is invoked
       
  1072 ** following a call to sqlite3_shutdown().  ^(Only an effective call
       
  1073 ** of sqlite3_initialize() does any initialization.  All other calls
       
  1074 ** are harmless no-ops.)^
       
  1075 **
       
  1076 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
       
  1077 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
       
  1078 ** an effective call to sqlite3_shutdown() does any deinitialization.
       
  1079 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
       
  1080 **
       
  1081 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
       
  1082 ** is not.  The sqlite3_shutdown() interface must only be called from a
       
  1083 ** single thread.  All open [database connections] must be closed and all
       
  1084 ** other SQLite resources must be deallocated prior to invoking
       
  1085 ** sqlite3_shutdown().
       
  1086 **
       
  1087 ** Among other things, ^sqlite3_initialize() will invoke
       
  1088 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
       
  1089 ** will invoke sqlite3_os_end().
       
  1090 **
       
  1091 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
       
  1092 ** ^If for some reason, sqlite3_initialize() is unable to initialize
       
  1093 ** the library (perhaps it is unable to allocate a needed resource such
       
  1094 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
       
  1095 **
       
  1096 ** ^The sqlite3_initialize() routine is called internally by many other
       
  1097 ** SQLite interfaces so that an application usually does not need to
       
  1098 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
       
  1099 ** calls sqlite3_initialize() so the SQLite library will be automatically
       
  1100 ** initialized when [sqlite3_open()] is called if it has not be initialized
       
  1101 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
       
  1102 ** compile-time option, then the automatic calls to sqlite3_initialize()
       
  1103 ** are omitted and the application must call sqlite3_initialize() directly
       
  1104 ** prior to using any other SQLite interface.  For maximum portability,
       
  1105 ** it is recommended that applications always invoke sqlite3_initialize()
       
  1106 ** directly prior to using any other SQLite interface.  Future releases
       
  1107 ** of SQLite may require this.  In other words, the behavior exhibited
       
  1108 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
       
  1109 ** default behavior in some future release of SQLite.
       
  1110 **
       
  1111 ** The sqlite3_os_init() routine does operating-system specific
       
  1112 ** initialization of the SQLite library.  The sqlite3_os_end()
       
  1113 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
       
  1114 ** performed by these routines include allocation or deallocation
       
  1115 ** of static resources, initialization of global variables,
       
  1116 ** setting up a default [sqlite3_vfs] module, or setting up
       
  1117 ** a default configuration using [sqlite3_config()].
       
  1118 **
       
  1119 ** The application should never invoke either sqlite3_os_init()
       
  1120 ** or sqlite3_os_end() directly.  The application should only invoke
       
  1121 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
       
  1122 ** interface is called automatically by sqlite3_initialize() and
       
  1123 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
       
  1124 ** implementations for sqlite3_os_init() and sqlite3_os_end()
       
  1125 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
       
  1126 ** When [custom builds | built for other platforms]
       
  1127 ** (using the [SQLITE_OS_OTHER=1] compile-time
       
  1128 ** option) the application must supply a suitable implementation for
       
  1129 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
       
  1130 ** implementation of sqlite3_os_init() or sqlite3_os_end()
       
  1131 ** must return [SQLITE_OK] on success and some other [error code] upon
       
  1132 ** failure.
       
  1133 */
       
  1134 SQLITE_API int sqlite3_initialize(void);
       
  1135 SQLITE_API int sqlite3_shutdown(void);
       
  1136 SQLITE_API int sqlite3_os_init(void);
       
  1137 SQLITE_API int sqlite3_os_end(void);
       
  1138 
       
  1139 /*
       
  1140 ** CAPI3REF: Configuring The SQLite Library
       
  1141 **
       
  1142 ** The sqlite3_config() interface is used to make global configuration
       
  1143 ** changes to SQLite in order to tune SQLite to the specific needs of
       
  1144 ** the application.  The default configuration is recommended for most
       
  1145 ** applications and so this routine is usually not necessary.  It is
       
  1146 ** provided to support rare applications with unusual needs.
       
  1147 **
       
  1148 ** The sqlite3_config() interface is not threadsafe.  The application
       
  1149 ** must insure that no other SQLite interfaces are invoked by other
       
  1150 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
       
  1151 ** may only be invoked prior to library initialization using
       
  1152 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
       
  1153 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
       
  1154 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
       
  1155 ** Note, however, that ^sqlite3_config() can be called as part of the
       
  1156 ** implementation of an application-defined [sqlite3_os_init()].
       
  1157 **
       
  1158 ** The first argument to sqlite3_config() is an integer
       
  1159 ** [configuration option] that determines
       
  1160 ** what property of SQLite is to be configured.  Subsequent arguments
       
  1161 ** vary depending on the [configuration option]
       
  1162 ** in the first argument.
       
  1163 **
       
  1164 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
       
  1165 ** ^If the option is unknown or SQLite is unable to set the option
       
  1166 ** then this routine returns a non-zero [error code].
       
  1167 */
       
  1168 SQLITE_API int sqlite3_config(int, ...);
       
  1169 
       
  1170 /*
       
  1171 ** CAPI3REF: Configure database connections
       
  1172 **
       
  1173 ** The sqlite3_db_config() interface is used to make configuration
       
  1174 ** changes to a [database connection].  The interface is similar to
       
  1175 ** [sqlite3_config()] except that the changes apply to a single
       
  1176 ** [database connection] (specified in the first argument).
       
  1177 **
       
  1178 ** The second argument to sqlite3_db_config(D,V,...)  is the
       
  1179 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 
       
  1180 ** that indicates what aspect of the [database connection] is being configured.
       
  1181 ** Subsequent arguments vary depending on the configuration verb.
       
  1182 **
       
  1183 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
       
  1184 ** the call is considered successful.
       
  1185 */
       
  1186 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
       
  1187 
       
  1188 /*
       
  1189 ** CAPI3REF: Memory Allocation Routines
       
  1190 **
       
  1191 ** An instance of this object defines the interface between SQLite
       
  1192 ** and low-level memory allocation routines.
       
  1193 **
       
  1194 ** This object is used in only one place in the SQLite interface.
       
  1195 ** A pointer to an instance of this object is the argument to
       
  1196 ** [sqlite3_config()] when the configuration option is
       
  1197 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].  
       
  1198 ** By creating an instance of this object
       
  1199 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
       
  1200 ** during configuration, an application can specify an alternative
       
  1201 ** memory allocation subsystem for SQLite to use for all of its
       
  1202 ** dynamic memory needs.
       
  1203 **
       
  1204 ** Note that SQLite comes with several [built-in memory allocators]
       
  1205 ** that are perfectly adequate for the overwhelming majority of applications
       
  1206 ** and that this object is only useful to a tiny minority of applications
       
  1207 ** with specialized memory allocation requirements.  This object is
       
  1208 ** also used during testing of SQLite in order to specify an alternative
       
  1209 ** memory allocator that simulates memory out-of-memory conditions in
       
  1210 ** order to verify that SQLite recovers gracefully from such
       
  1211 ** conditions.
       
  1212 **
       
  1213 ** The xMalloc, xRealloc, and xFree methods must work like the
       
  1214 ** malloc(), realloc() and free() functions from the standard C library.
       
  1215 ** ^SQLite guarantees that the second argument to
       
  1216 ** xRealloc is always a value returned by a prior call to xRoundup.
       
  1217 **
       
  1218 ** xSize should return the allocated size of a memory allocation
       
  1219 ** previously obtained from xMalloc or xRealloc.  The allocated size
       
  1220 ** is always at least as big as the requested size but may be larger.
       
  1221 **
       
  1222 ** The xRoundup method returns what would be the allocated size of
       
  1223 ** a memory allocation given a particular requested size.  Most memory
       
  1224 ** allocators round up memory allocations at least to the next multiple
       
  1225 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
       
  1226 ** Every memory allocation request coming in through [sqlite3_malloc()]
       
  1227 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0, 
       
  1228 ** that causes the corresponding memory allocation to fail.
       
  1229 **
       
  1230 ** The xInit method initializes the memory allocator.  (For example,
       
  1231 ** it might allocate any require mutexes or initialize internal data
       
  1232 ** structures.  The xShutdown method is invoked (indirectly) by
       
  1233 ** [sqlite3_shutdown()] and should deallocate any resources acquired
       
  1234 ** by xInit.  The pAppData pointer is used as the only parameter to
       
  1235 ** xInit and xShutdown.
       
  1236 **
       
  1237 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
       
  1238 ** the xInit method, so the xInit method need not be threadsafe.  The
       
  1239 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
       
  1240 ** not need to be threadsafe either.  For all other methods, SQLite
       
  1241 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
       
  1242 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
       
  1243 ** it is by default) and so the methods are automatically serialized.
       
  1244 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
       
  1245 ** methods must be threadsafe or else make their own arrangements for
       
  1246 ** serialization.
       
  1247 **
       
  1248 ** SQLite will never invoke xInit() more than once without an intervening
       
  1249 ** call to xShutdown().
       
  1250 */
       
  1251 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
       
  1252 struct sqlite3_mem_methods {
       
  1253   void *(*xMalloc)(int);         /* Memory allocation function */
       
  1254   void (*xFree)(void*);          /* Free a prior allocation */
       
  1255   void *(*xRealloc)(void*,int);  /* Resize an allocation */
       
  1256   int (*xSize)(void*);           /* Return the size of an allocation */
       
  1257   int (*xRoundup)(int);          /* Round up request size to allocation size */
       
  1258   int (*xInit)(void*);           /* Initialize the memory allocator */
       
  1259   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
       
  1260   void *pAppData;                /* Argument to xInit() and xShutdown() */
       
  1261 };
       
  1262 
       
  1263 /*
       
  1264 ** CAPI3REF: Configuration Options
       
  1265 ** KEYWORDS: {configuration option}
       
  1266 **
       
  1267 ** These constants are the available integer configuration options that
       
  1268 ** can be passed as the first argument to the [sqlite3_config()] interface.
       
  1269 **
       
  1270 ** New configuration options may be added in future releases of SQLite.
       
  1271 ** Existing configuration options might be discontinued.  Applications
       
  1272 ** should check the return code from [sqlite3_config()] to make sure that
       
  1273 ** the call worked.  The [sqlite3_config()] interface will return a
       
  1274 ** non-zero [error code] if a discontinued or unsupported configuration option
       
  1275 ** is invoked.
       
  1276 **
       
  1277 ** <dl>
       
  1278 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
       
  1279 ** <dd>There are no arguments to this option.  ^This option sets the
       
  1280 ** [threading mode] to Single-thread.  In other words, it disables
       
  1281 ** all mutexing and puts SQLite into a mode where it can only be used
       
  1282 ** by a single thread.   ^If SQLite is compiled with
       
  1283 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
       
  1284 ** it is not possible to change the [threading mode] from its default
       
  1285 ** value of Single-thread and so [sqlite3_config()] will return 
       
  1286 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
       
  1287 ** configuration option.</dd>
       
  1288 **
       
  1289 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
       
  1290 ** <dd>There are no arguments to this option.  ^This option sets the
       
  1291 ** [threading mode] to Multi-thread.  In other words, it disables
       
  1292 ** mutexing on [database connection] and [prepared statement] objects.
       
  1293 ** The application is responsible for serializing access to
       
  1294 ** [database connections] and [prepared statements].  But other mutexes
       
  1295 ** are enabled so that SQLite will be safe to use in a multi-threaded
       
  1296 ** environment as long as no two threads attempt to use the same
       
  1297 ** [database connection] at the same time.  ^If SQLite is compiled with
       
  1298 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
       
  1299 ** it is not possible to set the Multi-thread [threading mode] and
       
  1300 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
       
  1301 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
       
  1302 **
       
  1303 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
       
  1304 ** <dd>There are no arguments to this option.  ^This option sets the
       
  1305 ** [threading mode] to Serialized. In other words, this option enables
       
  1306 ** all mutexes including the recursive
       
  1307 ** mutexes on [database connection] and [prepared statement] objects.
       
  1308 ** In this mode (which is the default when SQLite is compiled with
       
  1309 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
       
  1310 ** to [database connections] and [prepared statements] so that the
       
  1311 ** application is free to use the same [database connection] or the
       
  1312 ** same [prepared statement] in different threads at the same time.
       
  1313 ** ^If SQLite is compiled with
       
  1314 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
       
  1315 ** it is not possible to set the Serialized [threading mode] and
       
  1316 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
       
  1317 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
       
  1318 **
       
  1319 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
       
  1320 ** <dd> ^(This option takes a single argument which is a pointer to an
       
  1321 ** instance of the [sqlite3_mem_methods] structure.  The argument specifies
       
  1322 ** alternative low-level memory allocation routines to be used in place of
       
  1323 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
       
  1324 ** its own private copy of the content of the [sqlite3_mem_methods] structure
       
  1325 ** before the [sqlite3_config()] call returns.</dd>
       
  1326 **
       
  1327 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
       
  1328 ** <dd> ^(This option takes a single argument which is a pointer to an
       
  1329 ** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
       
  1330 ** structure is filled with the currently defined memory allocation routines.)^
       
  1331 ** This option can be used to overload the default memory allocation
       
  1332 ** routines with a wrapper that simulations memory allocation failure or
       
  1333 ** tracks memory usage, for example. </dd>
       
  1334 **
       
  1335 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
       
  1336 ** <dd> ^This option takes single argument of type int, interpreted as a 
       
  1337 ** boolean, which enables or disables the collection of memory allocation 
       
  1338 ** statistics. ^(When memory allocation statistics are disabled, the 
       
  1339 ** following SQLite interfaces become non-operational:
       
  1340 **   <ul>
       
  1341 **   <li> [sqlite3_memory_used()]
       
  1342 **   <li> [sqlite3_memory_highwater()]
       
  1343 **   <li> [sqlite3_soft_heap_limit64()]
       
  1344 **   <li> [sqlite3_status()]
       
  1345 **   </ul>)^
       
  1346 ** ^Memory allocation statistics are enabled by default unless SQLite is
       
  1347 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
       
  1348 ** allocation statistics are disabled by default.
       
  1349 ** </dd>
       
  1350 **
       
  1351 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
       
  1352 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
       
  1353 ** scratch memory.  There are three arguments:  A pointer an 8-byte
       
  1354 ** aligned memory buffer from which the scratch allocations will be
       
  1355 ** drawn, the size of each scratch allocation (sz),
       
  1356 ** and the maximum number of scratch allocations (N).  The sz
       
  1357 ** argument must be a multiple of 16.
       
  1358 ** The first argument must be a pointer to an 8-byte aligned buffer
       
  1359 ** of at least sz*N bytes of memory.
       
  1360 ** ^SQLite will use no more than two scratch buffers per thread.  So
       
  1361 ** N should be set to twice the expected maximum number of threads.
       
  1362 ** ^SQLite will never require a scratch buffer that is more than 6
       
  1363 ** times the database page size. ^If SQLite needs needs additional
       
  1364 ** scratch memory beyond what is provided by this configuration option, then 
       
  1365 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
       
  1366 **
       
  1367 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
       
  1368 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
       
  1369 ** the database page cache with the default page cache implementation.  
       
  1370 ** This configuration should not be used if an application-define page
       
  1371 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
       
  1372 ** There are three arguments to this option: A pointer to 8-byte aligned
       
  1373 ** memory, the size of each page buffer (sz), and the number of pages (N).
       
  1374 ** The sz argument should be the size of the largest database page
       
  1375 ** (a power of two between 512 and 32768) plus a little extra for each
       
  1376 ** page header.  ^The page header size is 20 to 40 bytes depending on
       
  1377 ** the host architecture.  ^It is harmless, apart from the wasted memory,
       
  1378 ** to make sz a little too large.  The first
       
  1379 ** argument should point to an allocation of at least sz*N bytes of memory.
       
  1380 ** ^SQLite will use the memory provided by the first argument to satisfy its
       
  1381 ** memory needs for the first N pages that it adds to cache.  ^If additional
       
  1382 ** page cache memory is needed beyond what is provided by this option, then
       
  1383 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
       
  1384 ** The pointer in the first argument must
       
  1385 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
       
  1386 ** will be undefined.</dd>
       
  1387 **
       
  1388 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
       
  1389 ** <dd> ^This option specifies a static memory buffer that SQLite will use
       
  1390 ** for all of its dynamic memory allocation needs beyond those provided
       
  1391 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
       
  1392 ** There are three arguments: An 8-byte aligned pointer to the memory,
       
  1393 ** the number of bytes in the memory buffer, and the minimum allocation size.
       
  1394 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
       
  1395 ** to using its default memory allocator (the system malloc() implementation),
       
  1396 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
       
  1397 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
       
  1398 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
       
  1399 ** allocator is engaged to handle all of SQLites memory allocation needs.
       
  1400 ** The first pointer (the memory pointer) must be aligned to an 8-byte
       
  1401 ** boundary or subsequent behavior of SQLite will be undefined.
       
  1402 ** The minimum allocation size is capped at 2^12. Reasonable values
       
  1403 ** for the minimum allocation size are 2^5 through 2^8.</dd>
       
  1404 **
       
  1405 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
       
  1406 ** <dd> ^(This option takes a single argument which is a pointer to an
       
  1407 ** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
       
  1408 ** alternative low-level mutex routines to be used in place
       
  1409 ** the mutex routines built into SQLite.)^  ^SQLite makes a copy of the
       
  1410 ** content of the [sqlite3_mutex_methods] structure before the call to
       
  1411 ** [sqlite3_config()] returns. ^If SQLite is compiled with
       
  1412 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
       
  1413 ** the entire mutexing subsystem is omitted from the build and hence calls to
       
  1414 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
       
  1415 ** return [SQLITE_ERROR].</dd>
       
  1416 **
       
  1417 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
       
  1418 ** <dd> ^(This option takes a single argument which is a pointer to an
       
  1419 ** instance of the [sqlite3_mutex_methods] structure.  The
       
  1420 ** [sqlite3_mutex_methods]
       
  1421 ** structure is filled with the currently defined mutex routines.)^
       
  1422 ** This option can be used to overload the default mutex allocation
       
  1423 ** routines with a wrapper used to track mutex usage for performance
       
  1424 ** profiling or testing, for example.   ^If SQLite is compiled with
       
  1425 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
       
  1426 ** the entire mutexing subsystem is omitted from the build and hence calls to
       
  1427 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
       
  1428 ** return [SQLITE_ERROR].</dd>
       
  1429 **
       
  1430 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
       
  1431 ** <dd> ^(This option takes two arguments that determine the default
       
  1432 ** memory allocation for the lookaside memory allocator on each
       
  1433 ** [database connection].  The first argument is the
       
  1434 ** size of each lookaside buffer slot and the second is the number of
       
  1435 ** slots allocated to each database connection.)^  ^(This option sets the
       
  1436 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
       
  1437 ** verb to [sqlite3_db_config()] can be used to change the lookaside
       
  1438 ** configuration on individual connections.)^ </dd>
       
  1439 **
       
  1440 ** [[SQLITE_CONFIG_PCACHE]] <dt>SQLITE_CONFIG_PCACHE</dt>
       
  1441 ** <dd> ^(This option takes a single argument which is a pointer to
       
  1442 ** an [sqlite3_pcache_methods] object.  This object specifies the interface
       
  1443 ** to a custom page cache implementation.)^  ^SQLite makes a copy of the
       
  1444 ** object and uses it for page cache memory allocations.</dd>
       
  1445 **
       
  1446 ** [[SQLITE_CONFIG_GETPCACHE]] <dt>SQLITE_CONFIG_GETPCACHE</dt>
       
  1447 ** <dd> ^(This option takes a single argument which is a pointer to an
       
  1448 ** [sqlite3_pcache_methods] object.  SQLite copies of the current
       
  1449 ** page cache implementation into that object.)^ </dd>
       
  1450 **
       
  1451 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
       
  1452 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
       
  1453 ** function with a call signature of void(*)(void*,int,const char*), 
       
  1454 ** and a pointer to void. ^If the function pointer is not NULL, it is
       
  1455 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
       
  1456 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
       
  1457 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
       
  1458 ** passed through as the first parameter to the application-defined logger
       
  1459 ** function whenever that function is invoked.  ^The second parameter to
       
  1460 ** the logger function is a copy of the first parameter to the corresponding
       
  1461 ** [sqlite3_log()] call and is intended to be a [result code] or an
       
  1462 ** [extended result code].  ^The third parameter passed to the logger is
       
  1463 ** log message after formatting via [sqlite3_snprintf()].
       
  1464 ** The SQLite logging interface is not reentrant; the logger function
       
  1465 ** supplied by the application must not invoke any SQLite interface.
       
  1466 ** In a multi-threaded application, the application-defined logger
       
  1467 ** function must be threadsafe. </dd>
       
  1468 **
       
  1469 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
       
  1470 ** <dd> This option takes a single argument of type int. If non-zero, then
       
  1471 ** URI handling is globally enabled. If the parameter is zero, then URI handling
       
  1472 ** is globally disabled. If URI handling is globally enabled, all filenames
       
  1473 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
       
  1474 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
       
  1475 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
       
  1476 ** connection is opened. If it is globally disabled, filenames are
       
  1477 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
       
  1478 ** database connection is opened. By default, URI handling is globally
       
  1479 ** disabled. The default value may be changed by compiling with the
       
  1480 ** [SQLITE_USE_URI] symbol defined.
       
  1481 ** </dl>
       
  1482 */
       
  1483 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
       
  1484 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
       
  1485 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
       
  1486 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
       
  1487 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
       
  1488 #define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
       
  1489 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
       
  1490 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
       
  1491 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
       
  1492 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
       
  1493 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
       
  1494 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
       
  1495 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
       
  1496 #define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
       
  1497 #define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
       
  1498 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
       
  1499 #define SQLITE_CONFIG_URI          17  /* int */
       
  1500 
       
  1501 /*
       
  1502 ** CAPI3REF: Database Connection Configuration Options
       
  1503 **
       
  1504 ** These constants are the available integer configuration options that
       
  1505 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
       
  1506 **
       
  1507 ** New configuration options may be added in future releases of SQLite.
       
  1508 ** Existing configuration options might be discontinued.  Applications
       
  1509 ** should check the return code from [sqlite3_db_config()] to make sure that
       
  1510 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
       
  1511 ** non-zero [error code] if a discontinued or unsupported configuration option
       
  1512 ** is invoked.
       
  1513 **
       
  1514 ** <dl>
       
  1515 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
       
  1516 ** <dd> ^This option takes three additional arguments that determine the 
       
  1517 ** [lookaside memory allocator] configuration for the [database connection].
       
  1518 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
       
  1519 ** pointer to a memory buffer to use for lookaside memory.
       
  1520 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
       
  1521 ** may be NULL in which case SQLite will allocate the
       
  1522 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
       
  1523 ** size of each lookaside buffer slot.  ^The third argument is the number of
       
  1524 ** slots.  The size of the buffer in the first argument must be greater than
       
  1525 ** or equal to the product of the second and third arguments.  The buffer
       
  1526 ** must be aligned to an 8-byte boundary.  ^If the second argument to
       
  1527 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
       
  1528 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
       
  1529 ** configuration for a database connection can only be changed when that
       
  1530 ** connection is not currently using lookaside memory, or in other words
       
  1531 ** when the "current value" returned by
       
  1532 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
       
  1533 ** Any attempt to change the lookaside memory configuration when lookaside
       
  1534 ** memory is in use leaves the configuration unchanged and returns 
       
  1535 ** [SQLITE_BUSY].)^</dd>
       
  1536 **
       
  1537 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
       
  1538 ** <dd> ^This option is used to enable or disable the enforcement of
       
  1539 ** [foreign key constraints].  There should be two additional arguments.
       
  1540 ** The first argument is an integer which is 0 to disable FK enforcement,
       
  1541 ** positive to enable FK enforcement or negative to leave FK enforcement
       
  1542 ** unchanged.  The second parameter is a pointer to an integer into which
       
  1543 ** is written 0 or 1 to indicate whether FK enforcement is off or on
       
  1544 ** following this call.  The second parameter may be a NULL pointer, in
       
  1545 ** which case the FK enforcement setting is not reported back. </dd>
       
  1546 **
       
  1547 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
       
  1548 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
       
  1549 ** There should be two additional arguments.
       
  1550 ** The first argument is an integer which is 0 to disable triggers,
       
  1551 ** positive to enable triggers or negative to leave the setting unchanged.
       
  1552 ** The second parameter is a pointer to an integer into which
       
  1553 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
       
  1554 ** following this call.  The second parameter may be a NULL pointer, in
       
  1555 ** which case the trigger setting is not reported back. </dd>
       
  1556 **
       
  1557 ** </dl>
       
  1558 */
       
  1559 #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
       
  1560 #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
       
  1561 #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
       
  1562 
       
  1563 
       
  1564 /*
       
  1565 ** CAPI3REF: Enable Or Disable Extended Result Codes
       
  1566 **
       
  1567 ** ^The sqlite3_extended_result_codes() routine enables or disables the
       
  1568 ** [extended result codes] feature of SQLite. ^The extended result
       
  1569 ** codes are disabled by default for historical compatibility.
       
  1570 */
       
  1571 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
       
  1572 
       
  1573 /*
       
  1574 ** CAPI3REF: Last Insert Rowid
       
  1575 **
       
  1576 ** ^Each entry in an SQLite table has a unique 64-bit signed
       
  1577 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
       
  1578 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
       
  1579 ** names are not also used by explicitly declared columns. ^If
       
  1580 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
       
  1581 ** is another alias for the rowid.
       
  1582 **
       
  1583 ** ^This routine returns the [rowid] of the most recent
       
  1584 ** successful [INSERT] into the database from the [database connection]
       
  1585 ** in the first argument.  ^As of SQLite version 3.7.7, this routines
       
  1586 ** records the last insert rowid of both ordinary tables and [virtual tables].
       
  1587 ** ^If no successful [INSERT]s
       
  1588 ** have ever occurred on that database connection, zero is returned.
       
  1589 **
       
  1590 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
       
  1591 ** method, then this routine will return the [rowid] of the inserted
       
  1592 ** row as long as the trigger or virtual table method is running.
       
  1593 ** But once the trigger or virtual table method ends, the value returned 
       
  1594 ** by this routine reverts to what it was before the trigger or virtual
       
  1595 ** table method began.)^
       
  1596 **
       
  1597 ** ^An [INSERT] that fails due to a constraint violation is not a
       
  1598 ** successful [INSERT] and does not change the value returned by this
       
  1599 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
       
  1600 ** and INSERT OR ABORT make no changes to the return value of this
       
  1601 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
       
  1602 ** encounters a constraint violation, it does not fail.  The
       
  1603 ** INSERT continues to completion after deleting rows that caused
       
  1604 ** the constraint problem so INSERT OR REPLACE will always change
       
  1605 ** the return value of this interface.)^
       
  1606 **
       
  1607 ** ^For the purposes of this routine, an [INSERT] is considered to
       
  1608 ** be successful even if it is subsequently rolled back.
       
  1609 **
       
  1610 ** This function is accessible to SQL statements via the
       
  1611 ** [last_insert_rowid() SQL function].
       
  1612 **
       
  1613 ** If a separate thread performs a new [INSERT] on the same
       
  1614 ** database connection while the [sqlite3_last_insert_rowid()]
       
  1615 ** function is running and thus changes the last insert [rowid],
       
  1616 ** then the value returned by [sqlite3_last_insert_rowid()] is
       
  1617 ** unpredictable and might not equal either the old or the new
       
  1618 ** last insert [rowid].
       
  1619 */
       
  1620 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
       
  1621 
       
  1622 /*
       
  1623 ** CAPI3REF: Count The Number Of Rows Modified
       
  1624 **
       
  1625 ** ^This function returns the number of database rows that were changed
       
  1626 ** or inserted or deleted by the most recently completed SQL statement
       
  1627 ** on the [database connection] specified by the first parameter.
       
  1628 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
       
  1629 ** or [DELETE] statement are counted.  Auxiliary changes caused by
       
  1630 ** triggers or [foreign key actions] are not counted.)^ Use the
       
  1631 ** [sqlite3_total_changes()] function to find the total number of changes
       
  1632 ** including changes caused by triggers and foreign key actions.
       
  1633 **
       
  1634 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
       
  1635 ** are not counted.  Only real table changes are counted.
       
  1636 **
       
  1637 ** ^(A "row change" is a change to a single row of a single table
       
  1638 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
       
  1639 ** are changed as side effects of [REPLACE] constraint resolution,
       
  1640 ** rollback, ABORT processing, [DROP TABLE], or by any other
       
  1641 ** mechanisms do not count as direct row changes.)^
       
  1642 **
       
  1643 ** A "trigger context" is a scope of execution that begins and
       
  1644 ** ends with the script of a [CREATE TRIGGER | trigger]. 
       
  1645 ** Most SQL statements are
       
  1646 ** evaluated outside of any trigger.  This is the "top level"
       
  1647 ** trigger context.  If a trigger fires from the top level, a
       
  1648 ** new trigger context is entered for the duration of that one
       
  1649 ** trigger.  Subtriggers create subcontexts for their duration.
       
  1650 **
       
  1651 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
       
  1652 ** not create a new trigger context.
       
  1653 **
       
  1654 ** ^This function returns the number of direct row changes in the
       
  1655 ** most recent INSERT, UPDATE, or DELETE statement within the same
       
  1656 ** trigger context.
       
  1657 **
       
  1658 ** ^Thus, when called from the top level, this function returns the
       
  1659 ** number of changes in the most recent INSERT, UPDATE, or DELETE
       
  1660 ** that also occurred at the top level.  ^(Within the body of a trigger,
       
  1661 ** the sqlite3_changes() interface can be called to find the number of
       
  1662 ** changes in the most recently completed INSERT, UPDATE, or DELETE
       
  1663 ** statement within the body of the same trigger.
       
  1664 ** However, the number returned does not include changes
       
  1665 ** caused by subtriggers since those have their own context.)^
       
  1666 **
       
  1667 ** See also the [sqlite3_total_changes()] interface, the
       
  1668 ** [count_changes pragma], and the [changes() SQL function].
       
  1669 **
       
  1670 ** If a separate thread makes changes on the same database connection
       
  1671 ** while [sqlite3_changes()] is running then the value returned
       
  1672 ** is unpredictable and not meaningful.
       
  1673 */
       
  1674 SQLITE_API int sqlite3_changes(sqlite3*);
       
  1675 
       
  1676 /*
       
  1677 ** CAPI3REF: Total Number Of Rows Modified
       
  1678 **
       
  1679 ** ^This function returns the number of row changes caused by [INSERT],
       
  1680 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
       
  1681 ** ^(The count returned by sqlite3_total_changes() includes all changes
       
  1682 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
       
  1683 ** [foreign key actions]. However,
       
  1684 ** the count does not include changes used to implement [REPLACE] constraints,
       
  1685 ** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
       
  1686 ** count does not include rows of views that fire an [INSTEAD OF trigger],
       
  1687 ** though if the INSTEAD OF trigger makes changes of its own, those changes 
       
  1688 ** are counted.)^
       
  1689 ** ^The sqlite3_total_changes() function counts the changes as soon as
       
  1690 ** the statement that makes them is completed (when the statement handle
       
  1691 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
       
  1692 **
       
  1693 ** See also the [sqlite3_changes()] interface, the
       
  1694 ** [count_changes pragma], and the [total_changes() SQL function].
       
  1695 **
       
  1696 ** If a separate thread makes changes on the same database connection
       
  1697 ** while [sqlite3_total_changes()] is running then the value
       
  1698 ** returned is unpredictable and not meaningful.
       
  1699 */
       
  1700 SQLITE_API int sqlite3_total_changes(sqlite3*);
       
  1701 
       
  1702 /*
       
  1703 ** CAPI3REF: Interrupt A Long-Running Query
       
  1704 **
       
  1705 ** ^This function causes any pending database operation to abort and
       
  1706 ** return at its earliest opportunity. This routine is typically
       
  1707 ** called in response to a user action such as pressing "Cancel"
       
  1708 ** or Ctrl-C where the user wants a long query operation to halt
       
  1709 ** immediately.
       
  1710 **
       
  1711 ** ^It is safe to call this routine from a thread different from the
       
  1712 ** thread that is currently running the database operation.  But it
       
  1713 ** is not safe to call this routine with a [database connection] that
       
  1714 ** is closed or might close before sqlite3_interrupt() returns.
       
  1715 **
       
  1716 ** ^If an SQL operation is very nearly finished at the time when
       
  1717 ** sqlite3_interrupt() is called, then it might not have an opportunity
       
  1718 ** to be interrupted and might continue to completion.
       
  1719 **
       
  1720 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
       
  1721 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
       
  1722 ** that is inside an explicit transaction, then the entire transaction
       
  1723 ** will be rolled back automatically.
       
  1724 **
       
  1725 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
       
  1726 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
       
  1727 ** that are started after the sqlite3_interrupt() call and before the 
       
  1728 ** running statements reaches zero are interrupted as if they had been
       
  1729 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
       
  1730 ** that are started after the running statement count reaches zero are
       
  1731 ** not effected by the sqlite3_interrupt().
       
  1732 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
       
  1733 ** SQL statements is a no-op and has no effect on SQL statements
       
  1734 ** that are started after the sqlite3_interrupt() call returns.
       
  1735 **
       
  1736 ** If the database connection closes while [sqlite3_interrupt()]
       
  1737 ** is running then bad things will likely happen.
       
  1738 */
       
  1739 SQLITE_API void sqlite3_interrupt(sqlite3*);
       
  1740 
       
  1741 /*
       
  1742 ** CAPI3REF: Determine If An SQL Statement Is Complete
       
  1743 **
       
  1744 ** These routines are useful during command-line input to determine if the
       
  1745 ** currently entered text seems to form a complete SQL statement or
       
  1746 ** if additional input is needed before sending the text into
       
  1747 ** SQLite for parsing.  ^These routines return 1 if the input string
       
  1748 ** appears to be a complete SQL statement.  ^A statement is judged to be
       
  1749 ** complete if it ends with a semicolon token and is not a prefix of a
       
  1750 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
       
  1751 ** string literals or quoted identifier names or comments are not
       
  1752 ** independent tokens (they are part of the token in which they are
       
  1753 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
       
  1754 ** and comments that follow the final semicolon are ignored.
       
  1755 **
       
  1756 ** ^These routines return 0 if the statement is incomplete.  ^If a
       
  1757 ** memory allocation fails, then SQLITE_NOMEM is returned.
       
  1758 **
       
  1759 ** ^These routines do not parse the SQL statements thus
       
  1760 ** will not detect syntactically incorrect SQL.
       
  1761 **
       
  1762 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 
       
  1763 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
       
  1764 ** automatically by sqlite3_complete16().  If that initialization fails,
       
  1765 ** then the return value from sqlite3_complete16() will be non-zero
       
  1766 ** regardless of whether or not the input SQL is complete.)^
       
  1767 **
       
  1768 ** The input to [sqlite3_complete()] must be a zero-terminated
       
  1769 ** UTF-8 string.
       
  1770 **
       
  1771 ** The input to [sqlite3_complete16()] must be a zero-terminated
       
  1772 ** UTF-16 string in native byte order.
       
  1773 */
       
  1774 SQLITE_API int sqlite3_complete(const char *sql);
       
  1775 SQLITE_API int sqlite3_complete16(const void *sql);
       
  1776 
       
  1777 /*
       
  1778 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
       
  1779 **
       
  1780 ** ^This routine sets a callback function that might be invoked whenever
       
  1781 ** an attempt is made to open a database table that another thread
       
  1782 ** or process has locked.
       
  1783 **
       
  1784 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
       
  1785 ** is returned immediately upon encountering the lock.  ^If the busy callback
       
  1786 ** is not NULL, then the callback might be invoked with two arguments.
       
  1787 **
       
  1788 ** ^The first argument to the busy handler is a copy of the void* pointer which
       
  1789 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
       
  1790 ** the busy handler callback is the number of times that the busy handler has
       
  1791 ** been invoked for this locking event.  ^If the
       
  1792 ** busy callback returns 0, then no additional attempts are made to
       
  1793 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
       
  1794 ** ^If the callback returns non-zero, then another attempt
       
  1795 ** is made to open the database for reading and the cycle repeats.
       
  1796 **
       
  1797 ** The presence of a busy handler does not guarantee that it will be invoked
       
  1798 ** when there is lock contention. ^If SQLite determines that invoking the busy
       
  1799 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
       
  1800 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
       
  1801 ** Consider a scenario where one process is holding a read lock that
       
  1802 ** it is trying to promote to a reserved lock and
       
  1803 ** a second process is holding a reserved lock that it is trying
       
  1804 ** to promote to an exclusive lock.  The first process cannot proceed
       
  1805 ** because it is blocked by the second and the second process cannot
       
  1806 ** proceed because it is blocked by the first.  If both processes
       
  1807 ** invoke the busy handlers, neither will make any progress.  Therefore,
       
  1808 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
       
  1809 ** will induce the first process to release its read lock and allow
       
  1810 ** the second process to proceed.
       
  1811 **
       
  1812 ** ^The default busy callback is NULL.
       
  1813 **
       
  1814 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
       
  1815 ** when SQLite is in the middle of a large transaction where all the
       
  1816 ** changes will not fit into the in-memory cache.  SQLite will
       
  1817 ** already hold a RESERVED lock on the database file, but it needs
       
  1818 ** to promote this lock to EXCLUSIVE so that it can spill cache
       
  1819 ** pages into the database file without harm to concurrent
       
  1820 ** readers.  ^If it is unable to promote the lock, then the in-memory
       
  1821 ** cache will be left in an inconsistent state and so the error
       
  1822 ** code is promoted from the relatively benign [SQLITE_BUSY] to
       
  1823 ** the more severe [SQLITE_IOERR_BLOCKED].  ^This error code promotion
       
  1824 ** forces an automatic rollback of the changes.  See the
       
  1825 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
       
  1826 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
       
  1827 ** this is important.
       
  1828 **
       
  1829 ** ^(There can only be a single busy handler defined for each
       
  1830 ** [database connection].  Setting a new busy handler clears any
       
  1831 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
       
  1832 ** will also set or clear the busy handler.
       
  1833 **
       
  1834 ** The busy callback should not take any actions which modify the
       
  1835 ** database connection that invoked the busy handler.  Any such actions
       
  1836 ** result in undefined behavior.
       
  1837 ** 
       
  1838 ** A busy handler must not close the database connection
       
  1839 ** or [prepared statement] that invoked the busy handler.
       
  1840 */
       
  1841 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
       
  1842 
       
  1843 /*
       
  1844 ** CAPI3REF: Set A Busy Timeout
       
  1845 **
       
  1846 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
       
  1847 ** for a specified amount of time when a table is locked.  ^The handler
       
  1848 ** will sleep multiple times until at least "ms" milliseconds of sleeping
       
  1849 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
       
  1850 ** the handler returns 0 which causes [sqlite3_step()] to return
       
  1851 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
       
  1852 **
       
  1853 ** ^Calling this routine with an argument less than or equal to zero
       
  1854 ** turns off all busy handlers.
       
  1855 **
       
  1856 ** ^(There can only be a single busy handler for a particular
       
  1857 ** [database connection] any any given moment.  If another busy handler
       
  1858 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
       
  1859 ** this routine, that other busy handler is cleared.)^
       
  1860 */
       
  1861 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
       
  1862 
       
  1863 /*
       
  1864 ** CAPI3REF: Convenience Routines For Running Queries
       
  1865 **
       
  1866 ** This is a legacy interface that is preserved for backwards compatibility.
       
  1867 ** Use of this interface is not recommended.
       
  1868 **
       
  1869 ** Definition: A <b>result table</b> is memory data structure created by the
       
  1870 ** [sqlite3_get_table()] interface.  A result table records the
       
  1871 ** complete query results from one or more queries.
       
  1872 **
       
  1873 ** The table conceptually has a number of rows and columns.  But
       
  1874 ** these numbers are not part of the result table itself.  These
       
  1875 ** numbers are obtained separately.  Let N be the number of rows
       
  1876 ** and M be the number of columns.
       
  1877 **
       
  1878 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
       
  1879 ** There are (N+1)*M elements in the array.  The first M pointers point
       
  1880 ** to zero-terminated strings that  contain the names of the columns.
       
  1881 ** The remaining entries all point to query results.  NULL values result
       
  1882 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
       
  1883 ** string representation as returned by [sqlite3_column_text()].
       
  1884 **
       
  1885 ** A result table might consist of one or more memory allocations.
       
  1886 ** It is not safe to pass a result table directly to [sqlite3_free()].
       
  1887 ** A result table should be deallocated using [sqlite3_free_table()].
       
  1888 **
       
  1889 ** ^(As an example of the result table format, suppose a query result
       
  1890 ** is as follows:
       
  1891 **
       
  1892 ** <blockquote><pre>
       
  1893 **        Name        | Age
       
  1894 **        -----------------------
       
  1895 **        Alice       | 43
       
  1896 **        Bob         | 28
       
  1897 **        Cindy       | 21
       
  1898 ** </pre></blockquote>
       
  1899 **
       
  1900 ** There are two column (M==2) and three rows (N==3).  Thus the
       
  1901 ** result table has 8 entries.  Suppose the result table is stored
       
  1902 ** in an array names azResult.  Then azResult holds this content:
       
  1903 **
       
  1904 ** <blockquote><pre>
       
  1905 **        azResult&#91;0] = "Name";
       
  1906 **        azResult&#91;1] = "Age";
       
  1907 **        azResult&#91;2] = "Alice";
       
  1908 **        azResult&#91;3] = "43";
       
  1909 **        azResult&#91;4] = "Bob";
       
  1910 **        azResult&#91;5] = "28";
       
  1911 **        azResult&#91;6] = "Cindy";
       
  1912 **        azResult&#91;7] = "21";
       
  1913 ** </pre></blockquote>)^
       
  1914 **
       
  1915 ** ^The sqlite3_get_table() function evaluates one or more
       
  1916 ** semicolon-separated SQL statements in the zero-terminated UTF-8
       
  1917 ** string of its 2nd parameter and returns a result table to the
       
  1918 ** pointer given in its 3rd parameter.
       
  1919 **
       
  1920 ** After the application has finished with the result from sqlite3_get_table(),
       
  1921 ** it must pass the result table pointer to sqlite3_free_table() in order to
       
  1922 ** release the memory that was malloced.  Because of the way the
       
  1923 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
       
  1924 ** function must not try to call [sqlite3_free()] directly.  Only
       
  1925 ** [sqlite3_free_table()] is able to release the memory properly and safely.
       
  1926 **
       
  1927 ** The sqlite3_get_table() interface is implemented as a wrapper around
       
  1928 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
       
  1929 ** to any internal data structures of SQLite.  It uses only the public
       
  1930 ** interface defined here.  As a consequence, errors that occur in the
       
  1931 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
       
  1932 ** reflected in subsequent calls to [sqlite3_errcode()] or
       
  1933 ** [sqlite3_errmsg()].
       
  1934 */
       
  1935 SQLITE_API int sqlite3_get_table(
       
  1936   sqlite3 *db,          /* An open database */
       
  1937   const char *zSql,     /* SQL to be evaluated */
       
  1938   char ***pazResult,    /* Results of the query */
       
  1939   int *pnRow,           /* Number of result rows written here */
       
  1940   int *pnColumn,        /* Number of result columns written here */
       
  1941   char **pzErrmsg       /* Error msg written here */
       
  1942 );
       
  1943 SQLITE_API void sqlite3_free_table(char **result);
       
  1944 
       
  1945 /*
       
  1946 ** CAPI3REF: Formatted String Printing Functions
       
  1947 **
       
  1948 ** These routines are work-alikes of the "printf()" family of functions
       
  1949 ** from the standard C library.
       
  1950 **
       
  1951 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
       
  1952 ** results into memory obtained from [sqlite3_malloc()].
       
  1953 ** The strings returned by these two routines should be
       
  1954 ** released by [sqlite3_free()].  ^Both routines return a
       
  1955 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
       
  1956 ** memory to hold the resulting string.
       
  1957 **
       
  1958 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
       
  1959 ** the standard C library.  The result is written into the
       
  1960 ** buffer supplied as the second parameter whose size is given by
       
  1961 ** the first parameter. Note that the order of the
       
  1962 ** first two parameters is reversed from snprintf().)^  This is an
       
  1963 ** historical accident that cannot be fixed without breaking
       
  1964 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
       
  1965 ** returns a pointer to its buffer instead of the number of
       
  1966 ** characters actually written into the buffer.)^  We admit that
       
  1967 ** the number of characters written would be a more useful return
       
  1968 ** value but we cannot change the implementation of sqlite3_snprintf()
       
  1969 ** now without breaking compatibility.
       
  1970 **
       
  1971 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
       
  1972 ** guarantees that the buffer is always zero-terminated.  ^The first
       
  1973 ** parameter "n" is the total size of the buffer, including space for
       
  1974 ** the zero terminator.  So the longest string that can be completely
       
  1975 ** written will be n-1 characters.
       
  1976 **
       
  1977 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
       
  1978 **
       
  1979 ** These routines all implement some additional formatting
       
  1980 ** options that are useful for constructing SQL statements.
       
  1981 ** All of the usual printf() formatting options apply.  In addition, there
       
  1982 ** is are "%q", "%Q", and "%z" options.
       
  1983 **
       
  1984 ** ^(The %q option works like %s in that it substitutes a null-terminated
       
  1985 ** string from the argument list.  But %q also doubles every '\'' character.
       
  1986 ** %q is designed for use inside a string literal.)^  By doubling each '\''
       
  1987 ** character it escapes that character and allows it to be inserted into
       
  1988 ** the string.
       
  1989 **
       
  1990 ** For example, assume the string variable zText contains text as follows:
       
  1991 **
       
  1992 ** <blockquote><pre>
       
  1993 **  char *zText = "It's a happy day!";
       
  1994 ** </pre></blockquote>
       
  1995 **
       
  1996 ** One can use this text in an SQL statement as follows:
       
  1997 **
       
  1998 ** <blockquote><pre>
       
  1999 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
       
  2000 **  sqlite3_exec(db, zSQL, 0, 0, 0);
       
  2001 **  sqlite3_free(zSQL);
       
  2002 ** </pre></blockquote>
       
  2003 **
       
  2004 ** Because the %q format string is used, the '\'' character in zText
       
  2005 ** is escaped and the SQL generated is as follows:
       
  2006 **
       
  2007 ** <blockquote><pre>
       
  2008 **  INSERT INTO table1 VALUES('It''s a happy day!')
       
  2009 ** </pre></blockquote>
       
  2010 **
       
  2011 ** This is correct.  Had we used %s instead of %q, the generated SQL
       
  2012 ** would have looked like this:
       
  2013 **
       
  2014 ** <blockquote><pre>
       
  2015 **  INSERT INTO table1 VALUES('It's a happy day!');
       
  2016 ** </pre></blockquote>
       
  2017 **
       
  2018 ** This second example is an SQL syntax error.  As a general rule you should
       
  2019 ** always use %q instead of %s when inserting text into a string literal.
       
  2020 **
       
  2021 ** ^(The %Q option works like %q except it also adds single quotes around
       
  2022 ** the outside of the total string.  Additionally, if the parameter in the
       
  2023 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
       
  2024 ** single quotes).)^  So, for example, one could say:
       
  2025 **
       
  2026 ** <blockquote><pre>
       
  2027 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
       
  2028 **  sqlite3_exec(db, zSQL, 0, 0, 0);
       
  2029 **  sqlite3_free(zSQL);
       
  2030 ** </pre></blockquote>
       
  2031 **
       
  2032 ** The code above will render a correct SQL statement in the zSQL
       
  2033 ** variable even if the zText variable is a NULL pointer.
       
  2034 **
       
  2035 ** ^(The "%z" formatting option works like "%s" but with the
       
  2036 ** addition that after the string has been read and copied into
       
  2037 ** the result, [sqlite3_free()] is called on the input string.)^
       
  2038 */
       
  2039 SQLITE_API char *sqlite3_mprintf(const char*,...);
       
  2040 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
       
  2041 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
       
  2042 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
       
  2043 
       
  2044 /*
       
  2045 ** CAPI3REF: Memory Allocation Subsystem
       
  2046 **
       
  2047 ** The SQLite core uses these three routines for all of its own
       
  2048 ** internal memory allocation needs. "Core" in the previous sentence
       
  2049 ** does not include operating-system specific VFS implementation.  The
       
  2050 ** Windows VFS uses native malloc() and free() for some operations.
       
  2051 **
       
  2052 ** ^The sqlite3_malloc() routine returns a pointer to a block
       
  2053 ** of memory at least N bytes in length, where N is the parameter.
       
  2054 ** ^If sqlite3_malloc() is unable to obtain sufficient free
       
  2055 ** memory, it returns a NULL pointer.  ^If the parameter N to
       
  2056 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
       
  2057 ** a NULL pointer.
       
  2058 **
       
  2059 ** ^Calling sqlite3_free() with a pointer previously returned
       
  2060 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
       
  2061 ** that it might be reused.  ^The sqlite3_free() routine is
       
  2062 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
       
  2063 ** to sqlite3_free() is harmless.  After being freed, memory
       
  2064 ** should neither be read nor written.  Even reading previously freed
       
  2065 ** memory might result in a segmentation fault or other severe error.
       
  2066 ** Memory corruption, a segmentation fault, or other severe error
       
  2067 ** might result if sqlite3_free() is called with a non-NULL pointer that
       
  2068 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
       
  2069 **
       
  2070 ** ^(The sqlite3_realloc() interface attempts to resize a
       
  2071 ** prior memory allocation to be at least N bytes, where N is the
       
  2072 ** second parameter.  The memory allocation to be resized is the first
       
  2073 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
       
  2074 ** is a NULL pointer then its behavior is identical to calling
       
  2075 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
       
  2076 ** ^If the second parameter to sqlite3_realloc() is zero or
       
  2077 ** negative then the behavior is exactly the same as calling
       
  2078 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
       
  2079 ** ^sqlite3_realloc() returns a pointer to a memory allocation
       
  2080 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
       
  2081 ** ^If M is the size of the prior allocation, then min(N,M) bytes
       
  2082 ** of the prior allocation are copied into the beginning of buffer returned
       
  2083 ** by sqlite3_realloc() and the prior allocation is freed.
       
  2084 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
       
  2085 ** is not freed.
       
  2086 **
       
  2087 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
       
  2088 ** is always aligned to at least an 8 byte boundary, or to a
       
  2089 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
       
  2090 ** option is used.
       
  2091 **
       
  2092 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
       
  2093 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
       
  2094 ** implementation of these routines to be omitted.  That capability
       
  2095 ** is no longer provided.  Only built-in memory allocators can be used.
       
  2096 **
       
  2097 ** The Windows OS interface layer calls
       
  2098 ** the system malloc() and free() directly when converting
       
  2099 ** filenames between the UTF-8 encoding used by SQLite
       
  2100 ** and whatever filename encoding is used by the particular Windows
       
  2101 ** installation.  Memory allocation errors are detected, but
       
  2102 ** they are reported back as [SQLITE_CANTOPEN] or
       
  2103 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
       
  2104 **
       
  2105 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
       
  2106 ** must be either NULL or else pointers obtained from a prior
       
  2107 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
       
  2108 ** not yet been released.
       
  2109 **
       
  2110 ** The application must not read or write any part of
       
  2111 ** a block of memory after it has been released using
       
  2112 ** [sqlite3_free()] or [sqlite3_realloc()].
       
  2113 */
       
  2114 SQLITE_API void *sqlite3_malloc(int);
       
  2115 SQLITE_API void *sqlite3_realloc(void*, int);
       
  2116 SQLITE_API void sqlite3_free(void*);
       
  2117 
       
  2118 /*
       
  2119 ** CAPI3REF: Memory Allocator Statistics
       
  2120 **
       
  2121 ** SQLite provides these two interfaces for reporting on the status
       
  2122 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
       
  2123 ** routines, which form the built-in memory allocation subsystem.
       
  2124 **
       
  2125 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
       
  2126 ** of memory currently outstanding (malloced but not freed).
       
  2127 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
       
  2128 ** value of [sqlite3_memory_used()] since the high-water mark
       
  2129 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
       
  2130 ** [sqlite3_memory_highwater()] include any overhead
       
  2131 ** added by SQLite in its implementation of [sqlite3_malloc()],
       
  2132 ** but not overhead added by the any underlying system library
       
  2133 ** routines that [sqlite3_malloc()] may call.
       
  2134 **
       
  2135 ** ^The memory high-water mark is reset to the current value of
       
  2136 ** [sqlite3_memory_used()] if and only if the parameter to
       
  2137 ** [sqlite3_memory_highwater()] is true.  ^The value returned
       
  2138 ** by [sqlite3_memory_highwater(1)] is the high-water mark
       
  2139 ** prior to the reset.
       
  2140 */
       
  2141 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
       
  2142 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
       
  2143 
       
  2144 /*
       
  2145 ** CAPI3REF: Pseudo-Random Number Generator
       
  2146 **
       
  2147 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
       
  2148 ** select random [ROWID | ROWIDs] when inserting new records into a table that
       
  2149 ** already uses the largest possible [ROWID].  The PRNG is also used for
       
  2150 ** the build-in random() and randomblob() SQL functions.  This interface allows
       
  2151 ** applications to access the same PRNG for other purposes.
       
  2152 **
       
  2153 ** ^A call to this routine stores N bytes of randomness into buffer P.
       
  2154 **
       
  2155 ** ^The first time this routine is invoked (either internally or by
       
  2156 ** the application) the PRNG is seeded using randomness obtained
       
  2157 ** from the xRandomness method of the default [sqlite3_vfs] object.
       
  2158 ** ^On all subsequent invocations, the pseudo-randomness is generated
       
  2159 ** internally and without recourse to the [sqlite3_vfs] xRandomness
       
  2160 ** method.
       
  2161 */
       
  2162 SQLITE_API void sqlite3_randomness(int N, void *P);
       
  2163 
       
  2164 /*
       
  2165 ** CAPI3REF: Compile-Time Authorization Callbacks
       
  2166 **
       
  2167 ** ^This routine registers an authorizer callback with a particular
       
  2168 ** [database connection], supplied in the first argument.
       
  2169 ** ^The authorizer callback is invoked as SQL statements are being compiled
       
  2170 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
       
  2171 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
       
  2172 ** points during the compilation process, as logic is being created
       
  2173 ** to perform various actions, the authorizer callback is invoked to
       
  2174 ** see if those actions are allowed.  ^The authorizer callback should
       
  2175 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
       
  2176 ** specific action but allow the SQL statement to continue to be
       
  2177 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
       
  2178 ** rejected with an error.  ^If the authorizer callback returns
       
  2179 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
       
  2180 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
       
  2181 ** the authorizer will fail with an error message.
       
  2182 **
       
  2183 ** When the callback returns [SQLITE_OK], that means the operation
       
  2184 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
       
  2185 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
       
  2186 ** authorizer will fail with an error message explaining that
       
  2187 ** access is denied. 
       
  2188 **
       
  2189 ** ^The first parameter to the authorizer callback is a copy of the third
       
  2190 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
       
  2191 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
       
  2192 ** the particular action to be authorized. ^The third through sixth parameters
       
  2193 ** to the callback are zero-terminated strings that contain additional
       
  2194 ** details about the action to be authorized.
       
  2195 **
       
  2196 ** ^If the action code is [SQLITE_READ]
       
  2197 ** and the callback returns [SQLITE_IGNORE] then the
       
  2198 ** [prepared statement] statement is constructed to substitute
       
  2199 ** a NULL value in place of the table column that would have
       
  2200 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
       
  2201 ** return can be used to deny an untrusted user access to individual
       
  2202 ** columns of a table.
       
  2203 ** ^If the action code is [SQLITE_DELETE] and the callback returns
       
  2204 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
       
  2205 ** [truncate optimization] is disabled and all rows are deleted individually.
       
  2206 **
       
  2207 ** An authorizer is used when [sqlite3_prepare | preparing]
       
  2208 ** SQL statements from an untrusted source, to ensure that the SQL statements
       
  2209 ** do not try to access data they are not allowed to see, or that they do not
       
  2210 ** try to execute malicious statements that damage the database.  For
       
  2211 ** example, an application may allow a user to enter arbitrary
       
  2212 ** SQL queries for evaluation by a database.  But the application does
       
  2213 ** not want the user to be able to make arbitrary changes to the
       
  2214 ** database.  An authorizer could then be put in place while the
       
  2215 ** user-entered SQL is being [sqlite3_prepare | prepared] that
       
  2216 ** disallows everything except [SELECT] statements.
       
  2217 **
       
  2218 ** Applications that need to process SQL from untrusted sources
       
  2219 ** might also consider lowering resource limits using [sqlite3_limit()]
       
  2220 ** and limiting database size using the [max_page_count] [PRAGMA]
       
  2221 ** in addition to using an authorizer.
       
  2222 **
       
  2223 ** ^(Only a single authorizer can be in place on a database connection
       
  2224 ** at a time.  Each call to sqlite3_set_authorizer overrides the
       
  2225 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
       
  2226 ** The authorizer is disabled by default.
       
  2227 **
       
  2228 ** The authorizer callback must not do anything that will modify
       
  2229 ** the database connection that invoked the authorizer callback.
       
  2230 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  2231 ** database connections for the meaning of "modify" in this paragraph.
       
  2232 **
       
  2233 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
       
  2234 ** statement might be re-prepared during [sqlite3_step()] due to a 
       
  2235 ** schema change.  Hence, the application should ensure that the
       
  2236 ** correct authorizer callback remains in place during the [sqlite3_step()].
       
  2237 **
       
  2238 ** ^Note that the authorizer callback is invoked only during
       
  2239 ** [sqlite3_prepare()] or its variants.  Authorization is not
       
  2240 ** performed during statement evaluation in [sqlite3_step()], unless
       
  2241 ** as stated in the previous paragraph, sqlite3_step() invokes
       
  2242 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
       
  2243 */
       
  2244 SQLITE_API int sqlite3_set_authorizer(
       
  2245   sqlite3*,
       
  2246   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
       
  2247   void *pUserData
       
  2248 );
       
  2249 
       
  2250 /*
       
  2251 ** CAPI3REF: Authorizer Return Codes
       
  2252 **
       
  2253 ** The [sqlite3_set_authorizer | authorizer callback function] must
       
  2254 ** return either [SQLITE_OK] or one of these two constants in order
       
  2255 ** to signal SQLite whether or not the action is permitted.  See the
       
  2256 ** [sqlite3_set_authorizer | authorizer documentation] for additional
       
  2257 ** information.
       
  2258 **
       
  2259 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
       
  2260 ** from the [sqlite3_vtab_on_conflict()] interface.
       
  2261 */
       
  2262 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
       
  2263 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
       
  2264 
       
  2265 /*
       
  2266 ** CAPI3REF: Authorizer Action Codes
       
  2267 **
       
  2268 ** The [sqlite3_set_authorizer()] interface registers a callback function
       
  2269 ** that is invoked to authorize certain SQL statement actions.  The
       
  2270 ** second parameter to the callback is an integer code that specifies
       
  2271 ** what action is being authorized.  These are the integer action codes that
       
  2272 ** the authorizer callback may be passed.
       
  2273 **
       
  2274 ** These action code values signify what kind of operation is to be
       
  2275 ** authorized.  The 3rd and 4th parameters to the authorization
       
  2276 ** callback function will be parameters or NULL depending on which of these
       
  2277 ** codes is used as the second parameter.  ^(The 5th parameter to the
       
  2278 ** authorizer callback is the name of the database ("main", "temp",
       
  2279 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
       
  2280 ** is the name of the inner-most trigger or view that is responsible for
       
  2281 ** the access attempt or NULL if this access attempt is directly from
       
  2282 ** top-level SQL code.
       
  2283 */
       
  2284 /******************************************* 3rd ************ 4th ***********/
       
  2285 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
       
  2286 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
       
  2287 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
       
  2288 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
       
  2289 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
       
  2290 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
       
  2291 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
       
  2292 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
       
  2293 #define SQLITE_DELETE                9   /* Table Name      NULL            */
       
  2294 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
       
  2295 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
       
  2296 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
       
  2297 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
       
  2298 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
       
  2299 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
       
  2300 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
       
  2301 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
       
  2302 #define SQLITE_INSERT               18   /* Table Name      NULL            */
       
  2303 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
       
  2304 #define SQLITE_READ                 20   /* Table Name      Column Name     */
       
  2305 #define SQLITE_SELECT               21   /* NULL            NULL            */
       
  2306 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
       
  2307 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
       
  2308 #define SQLITE_ATTACH               24   /* Filename        NULL            */
       
  2309 #define SQLITE_DETACH               25   /* Database Name   NULL            */
       
  2310 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
       
  2311 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
       
  2312 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
       
  2313 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
       
  2314 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
       
  2315 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
       
  2316 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
       
  2317 #define SQLITE_COPY                  0   /* No longer used */
       
  2318 
       
  2319 /*
       
  2320 ** CAPI3REF: Tracing And Profiling Functions
       
  2321 **
       
  2322 ** These routines register callback functions that can be used for
       
  2323 ** tracing and profiling the execution of SQL statements.
       
  2324 **
       
  2325 ** ^The callback function registered by sqlite3_trace() is invoked at
       
  2326 ** various times when an SQL statement is being run by [sqlite3_step()].
       
  2327 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
       
  2328 ** SQL statement text as the statement first begins executing.
       
  2329 ** ^(Additional sqlite3_trace() callbacks might occur
       
  2330 ** as each triggered subprogram is entered.  The callbacks for triggers
       
  2331 ** contain a UTF-8 SQL comment that identifies the trigger.)^
       
  2332 **
       
  2333 ** ^The callback function registered by sqlite3_profile() is invoked
       
  2334 ** as each SQL statement finishes.  ^The profile callback contains
       
  2335 ** the original statement text and an estimate of wall-clock time
       
  2336 ** of how long that statement took to run.  ^The profile callback
       
  2337 ** time is in units of nanoseconds, however the current implementation
       
  2338 ** is only capable of millisecond resolution so the six least significant
       
  2339 ** digits in the time are meaningless.  Future versions of SQLite
       
  2340 ** might provide greater resolution on the profiler callback.  The
       
  2341 ** sqlite3_profile() function is considered experimental and is
       
  2342 ** subject to change in future versions of SQLite.
       
  2343 */
       
  2344 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
       
  2345 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
       
  2346    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
       
  2347 
       
  2348 /*
       
  2349 ** CAPI3REF: Query Progress Callbacks
       
  2350 **
       
  2351 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
       
  2352 ** function X to be invoked periodically during long running calls to
       
  2353 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
       
  2354 ** database connection D.  An example use for this
       
  2355 ** interface is to keep a GUI updated during a large query.
       
  2356 **
       
  2357 ** ^The parameter P is passed through as the only parameter to the 
       
  2358 ** callback function X.  ^The parameter N is the number of 
       
  2359 ** [virtual machine instructions] that are evaluated between successive
       
  2360 ** invocations of the callback X.
       
  2361 **
       
  2362 ** ^Only a single progress handler may be defined at one time per
       
  2363 ** [database connection]; setting a new progress handler cancels the
       
  2364 ** old one.  ^Setting parameter X to NULL disables the progress handler.
       
  2365 ** ^The progress handler is also disabled by setting N to a value less
       
  2366 ** than 1.
       
  2367 **
       
  2368 ** ^If the progress callback returns non-zero, the operation is
       
  2369 ** interrupted.  This feature can be used to implement a
       
  2370 ** "Cancel" button on a GUI progress dialog box.
       
  2371 **
       
  2372 ** The progress handler callback must not do anything that will modify
       
  2373 ** the database connection that invoked the progress handler.
       
  2374 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  2375 ** database connections for the meaning of "modify" in this paragraph.
       
  2376 **
       
  2377 */
       
  2378 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
       
  2379 
       
  2380 /*
       
  2381 ** CAPI3REF: Opening A New Database Connection
       
  2382 **
       
  2383 ** ^These routines open an SQLite database file as specified by the 
       
  2384 ** filename argument. ^The filename argument is interpreted as UTF-8 for
       
  2385 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
       
  2386 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
       
  2387 ** returned in *ppDb, even if an error occurs.  The only exception is that
       
  2388 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
       
  2389 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
       
  2390 ** object.)^ ^(If the database is opened (and/or created) successfully, then
       
  2391 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
       
  2392 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
       
  2393 ** an English language description of the error following a failure of any
       
  2394 ** of the sqlite3_open() routines.
       
  2395 **
       
  2396 ** ^The default encoding for the database will be UTF-8 if
       
  2397 ** sqlite3_open() or sqlite3_open_v2() is called and
       
  2398 ** UTF-16 in the native byte order if sqlite3_open16() is used.
       
  2399 **
       
  2400 ** Whether or not an error occurs when it is opened, resources
       
  2401 ** associated with the [database connection] handle should be released by
       
  2402 ** passing it to [sqlite3_close()] when it is no longer required.
       
  2403 **
       
  2404 ** The sqlite3_open_v2() interface works like sqlite3_open()
       
  2405 ** except that it accepts two additional parameters for additional control
       
  2406 ** over the new database connection.  ^(The flags parameter to
       
  2407 ** sqlite3_open_v2() can take one of
       
  2408 ** the following three values, optionally combined with the 
       
  2409 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
       
  2410 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
       
  2411 **
       
  2412 ** <dl>
       
  2413 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
       
  2414 ** <dd>The database is opened in read-only mode.  If the database does not
       
  2415 ** already exist, an error is returned.</dd>)^
       
  2416 **
       
  2417 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
       
  2418 ** <dd>The database is opened for reading and writing if possible, or reading
       
  2419 ** only if the file is write protected by the operating system.  In either
       
  2420 ** case the database must already exist, otherwise an error is returned.</dd>)^
       
  2421 **
       
  2422 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
       
  2423 ** <dd>The database is opened for reading and writing, and is created if
       
  2424 ** it does not already exist. This is the behavior that is always used for
       
  2425 ** sqlite3_open() and sqlite3_open16().</dd>)^
       
  2426 ** </dl>
       
  2427 **
       
  2428 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
       
  2429 ** combinations shown above optionally combined with other
       
  2430 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
       
  2431 ** then the behavior is undefined.
       
  2432 **
       
  2433 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
       
  2434 ** opens in the multi-thread [threading mode] as long as the single-thread
       
  2435 ** mode has not been set at compile-time or start-time.  ^If the
       
  2436 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
       
  2437 ** in the serialized [threading mode] unless single-thread was
       
  2438 ** previously selected at compile-time or start-time.
       
  2439 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
       
  2440 ** eligible to use [shared cache mode], regardless of whether or not shared
       
  2441 ** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
       
  2442 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
       
  2443 ** participate in [shared cache mode] even if it is enabled.
       
  2444 **
       
  2445 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
       
  2446 ** [sqlite3_vfs] object that defines the operating system interface that
       
  2447 ** the new database connection should use.  ^If the fourth parameter is
       
  2448 ** a NULL pointer then the default [sqlite3_vfs] object is used.
       
  2449 **
       
  2450 ** ^If the filename is ":memory:", then a private, temporary in-memory database
       
  2451 ** is created for the connection.  ^This in-memory database will vanish when
       
  2452 ** the database connection is closed.  Future versions of SQLite might
       
  2453 ** make use of additional special filenames that begin with the ":" character.
       
  2454 ** It is recommended that when a database filename actually does begin with
       
  2455 ** a ":" character you should prefix the filename with a pathname such as
       
  2456 ** "./" to avoid ambiguity.
       
  2457 **
       
  2458 ** ^If the filename is an empty string, then a private, temporary
       
  2459 ** on-disk database will be created.  ^This private database will be
       
  2460 ** automatically deleted as soon as the database connection is closed.
       
  2461 **
       
  2462 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
       
  2463 **
       
  2464 ** ^If [URI filename] interpretation is enabled, and the filename argument
       
  2465 ** begins with "file:", then the filename is interpreted as a URI. ^URI
       
  2466 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
       
  2467 ** set in the fourth argument to sqlite3_open_v2(), or if it has
       
  2468 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
       
  2469 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
       
  2470 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
       
  2471 ** by default, but future releases of SQLite might enable URI filename
       
  2472 ** interpretation by default.  See "[URI filenames]" for additional
       
  2473 ** information.
       
  2474 **
       
  2475 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
       
  2476 ** authority, then it must be either an empty string or the string 
       
  2477 ** "localhost". ^If the authority is not an empty string or "localhost", an 
       
  2478 ** error is returned to the caller. ^The fragment component of a URI, if 
       
  2479 ** present, is ignored.
       
  2480 **
       
  2481 ** ^SQLite uses the path component of the URI as the name of the disk file
       
  2482 ** which contains the database. ^If the path begins with a '/' character, 
       
  2483 ** then it is interpreted as an absolute path. ^If the path does not begin 
       
  2484 ** with a '/' (meaning that the authority section is omitted from the URI)
       
  2485 ** then the path is interpreted as a relative path. 
       
  2486 ** ^On windows, the first component of an absolute path 
       
  2487 ** is a drive specification (e.g. "C:").
       
  2488 **
       
  2489 ** [[core URI query parameters]]
       
  2490 ** The query component of a URI may contain parameters that are interpreted
       
  2491 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
       
  2492 ** SQLite interprets the following three query parameters:
       
  2493 **
       
  2494 ** <ul>
       
  2495 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
       
  2496 **     a VFS object that provides the operating system interface that should
       
  2497 **     be used to access the database file on disk. ^If this option is set to
       
  2498 **     an empty string the default VFS object is used. ^Specifying an unknown
       
  2499 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
       
  2500 **     present, then the VFS specified by the option takes precedence over
       
  2501 **     the value passed as the fourth parameter to sqlite3_open_v2().
       
  2502 **
       
  2503 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or
       
  2504 **     "rwc". Attempting to set it to any other value is an error)^. 
       
  2505 **     ^If "ro" is specified, then the database is opened for read-only 
       
  2506 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 
       
  2507 **     third argument to sqlite3_prepare_v2(). ^If the mode option is set to 
       
  2508 **     "rw", then the database is opened for read-write (but not create) 
       
  2509 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 
       
  2510 **     been set. ^Value "rwc" is equivalent to setting both 
       
  2511 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 
       
  2512 **     used, it is an error to specify a value for the mode parameter that is 
       
  2513 **     less restrictive than that specified by the flags passed as the third 
       
  2514 **     parameter.
       
  2515 **
       
  2516 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
       
  2517 **     "private". ^Setting it to "shared" is equivalent to setting the
       
  2518 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
       
  2519 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
       
  2520 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
       
  2521 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
       
  2522 **     a URI filename, its value overrides any behaviour requested by setting
       
  2523 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
       
  2524 ** </ul>
       
  2525 **
       
  2526 ** ^Specifying an unknown parameter in the query component of a URI is not an
       
  2527 ** error.  Future versions of SQLite might understand additional query
       
  2528 ** parameters.  See "[query parameters with special meaning to SQLite]" for
       
  2529 ** additional information.
       
  2530 **
       
  2531 ** [[URI filename examples]] <h3>URI filename examples</h3>
       
  2532 **
       
  2533 ** <table border="1" align=center cellpadding=5>
       
  2534 ** <tr><th> URI filenames <th> Results
       
  2535 ** <tr><td> file:data.db <td> 
       
  2536 **          Open the file "data.db" in the current directory.
       
  2537 ** <tr><td> file:/home/fred/data.db<br>
       
  2538 **          file:///home/fred/data.db <br> 
       
  2539 **          file://localhost/home/fred/data.db <br> <td> 
       
  2540 **          Open the database file "/home/fred/data.db".
       
  2541 ** <tr><td> file://darkstar/home/fred/data.db <td> 
       
  2542 **          An error. "darkstar" is not a recognized authority.
       
  2543 ** <tr><td style="white-space:nowrap"> 
       
  2544 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
       
  2545 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
       
  2546 **          C:. Note that the %20 escaping in this example is not strictly 
       
  2547 **          necessary - space characters can be used literally
       
  2548 **          in URI filenames.
       
  2549 ** <tr><td> file:data.db?mode=ro&cache=private <td> 
       
  2550 **          Open file "data.db" in the current directory for read-only access.
       
  2551 **          Regardless of whether or not shared-cache mode is enabled by
       
  2552 **          default, use a private cache.
       
  2553 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
       
  2554 **          Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
       
  2555 ** <tr><td> file:data.db?mode=readonly <td> 
       
  2556 **          An error. "readonly" is not a valid option for the "mode" parameter.
       
  2557 ** </table>
       
  2558 **
       
  2559 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
       
  2560 ** query components of a URI. A hexadecimal escape sequence consists of a
       
  2561 ** percent sign - "%" - followed by exactly two hexadecimal digits 
       
  2562 ** specifying an octet value. ^Before the path or query components of a
       
  2563 ** URI filename are interpreted, they are encoded using UTF-8 and all 
       
  2564 ** hexadecimal escape sequences replaced by a single byte containing the
       
  2565 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
       
  2566 ** the results are undefined.
       
  2567 **
       
  2568 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
       
  2569 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
       
  2570 ** codepage is currently defined.  Filenames containing international
       
  2571 ** characters must be converted to UTF-8 prior to passing them into
       
  2572 ** sqlite3_open() or sqlite3_open_v2().
       
  2573 */
       
  2574 SQLITE_API int sqlite3_open(
       
  2575   const char *filename,   /* Database filename (UTF-8) */
       
  2576   sqlite3 **ppDb          /* OUT: SQLite db handle */
       
  2577 );
       
  2578 SQLITE_API int sqlite3_open16(
       
  2579   const void *filename,   /* Database filename (UTF-16) */
       
  2580   sqlite3 **ppDb          /* OUT: SQLite db handle */
       
  2581 );
       
  2582 SQLITE_API int sqlite3_open_v2(
       
  2583   const char *filename,   /* Database filename (UTF-8) */
       
  2584   sqlite3 **ppDb,         /* OUT: SQLite db handle */
       
  2585   int flags,              /* Flags */
       
  2586   const char *zVfs        /* Name of VFS module to use */
       
  2587 );
       
  2588 
       
  2589 /*
       
  2590 ** CAPI3REF: Obtain Values For URI Parameters
       
  2591 **
       
  2592 ** This is a utility routine, useful to VFS implementations, that checks
       
  2593 ** to see if a database file was a URI that contained a specific query 
       
  2594 ** parameter, and if so obtains the value of the query parameter.
       
  2595 **
       
  2596 ** The zFilename argument is the filename pointer passed into the xOpen()
       
  2597 ** method of a VFS implementation.  The zParam argument is the name of the
       
  2598 ** query parameter we seek.  This routine returns the value of the zParam
       
  2599 ** parameter if it exists.  If the parameter does not exist, this routine
       
  2600 ** returns a NULL pointer.
       
  2601 **
       
  2602 ** If the zFilename argument to this function is not a pointer that SQLite
       
  2603 ** passed into the xOpen VFS method, then the behavior of this routine
       
  2604 ** is undefined and probably undesirable.
       
  2605 */
       
  2606 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
       
  2607 
       
  2608 
       
  2609 /*
       
  2610 ** CAPI3REF: Error Codes And Messages
       
  2611 **
       
  2612 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
       
  2613 ** [extended result code] for the most recent failed sqlite3_* API call
       
  2614 ** associated with a [database connection]. If a prior API call failed
       
  2615 ** but the most recent API call succeeded, the return value from
       
  2616 ** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
       
  2617 ** interface is the same except that it always returns the 
       
  2618 ** [extended result code] even when extended result codes are
       
  2619 ** disabled.
       
  2620 **
       
  2621 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
       
  2622 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
       
  2623 ** ^(Memory to hold the error message string is managed internally.
       
  2624 ** The application does not need to worry about freeing the result.
       
  2625 ** However, the error string might be overwritten or deallocated by
       
  2626 ** subsequent calls to other SQLite interface functions.)^
       
  2627 **
       
  2628 ** When the serialized [threading mode] is in use, it might be the
       
  2629 ** case that a second error occurs on a separate thread in between
       
  2630 ** the time of the first error and the call to these interfaces.
       
  2631 ** When that happens, the second error will be reported since these
       
  2632 ** interfaces always report the most recent result.  To avoid
       
  2633 ** this, each thread can obtain exclusive use of the [database connection] D
       
  2634 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
       
  2635 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
       
  2636 ** all calls to the interfaces listed here are completed.
       
  2637 **
       
  2638 ** If an interface fails with SQLITE_MISUSE, that means the interface
       
  2639 ** was invoked incorrectly by the application.  In that case, the
       
  2640 ** error code and message may or may not be set.
       
  2641 */
       
  2642 SQLITE_API int sqlite3_errcode(sqlite3 *db);
       
  2643 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
       
  2644 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
       
  2645 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
       
  2646 
       
  2647 /*
       
  2648 ** CAPI3REF: SQL Statement Object
       
  2649 ** KEYWORDS: {prepared statement} {prepared statements}
       
  2650 **
       
  2651 ** An instance of this object represents a single SQL statement.
       
  2652 ** This object is variously known as a "prepared statement" or a
       
  2653 ** "compiled SQL statement" or simply as a "statement".
       
  2654 **
       
  2655 ** The life of a statement object goes something like this:
       
  2656 **
       
  2657 ** <ol>
       
  2658 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
       
  2659 **      function.
       
  2660 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
       
  2661 **      interfaces.
       
  2662 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
       
  2663 ** <li> Reset the statement using [sqlite3_reset()] then go back
       
  2664 **      to step 2.  Do this zero or more times.
       
  2665 ** <li> Destroy the object using [sqlite3_finalize()].
       
  2666 ** </ol>
       
  2667 **
       
  2668 ** Refer to documentation on individual methods above for additional
       
  2669 ** information.
       
  2670 */
       
  2671 typedef struct sqlite3_stmt sqlite3_stmt;
       
  2672 
       
  2673 /*
       
  2674 ** CAPI3REF: Run-time Limits
       
  2675 **
       
  2676 ** ^(This interface allows the size of various constructs to be limited
       
  2677 ** on a connection by connection basis.  The first parameter is the
       
  2678 ** [database connection] whose limit is to be set or queried.  The
       
  2679 ** second parameter is one of the [limit categories] that define a
       
  2680 ** class of constructs to be size limited.  The third parameter is the
       
  2681 ** new limit for that construct.)^
       
  2682 **
       
  2683 ** ^If the new limit is a negative number, the limit is unchanged.
       
  2684 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 
       
  2685 ** [limits | hard upper bound]
       
  2686 ** set at compile-time by a C preprocessor macro called
       
  2687 ** [limits | SQLITE_MAX_<i>NAME</i>].
       
  2688 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
       
  2689 ** ^Attempts to increase a limit above its hard upper bound are
       
  2690 ** silently truncated to the hard upper bound.
       
  2691 **
       
  2692 ** ^Regardless of whether or not the limit was changed, the 
       
  2693 ** [sqlite3_limit()] interface returns the prior value of the limit.
       
  2694 ** ^Hence, to find the current value of a limit without changing it,
       
  2695 ** simply invoke this interface with the third parameter set to -1.
       
  2696 **
       
  2697 ** Run-time limits are intended for use in applications that manage
       
  2698 ** both their own internal database and also databases that are controlled
       
  2699 ** by untrusted external sources.  An example application might be a
       
  2700 ** web browser that has its own databases for storing history and
       
  2701 ** separate databases controlled by JavaScript applications downloaded
       
  2702 ** off the Internet.  The internal databases can be given the
       
  2703 ** large, default limits.  Databases managed by external sources can
       
  2704 ** be given much smaller limits designed to prevent a denial of service
       
  2705 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
       
  2706 ** interface to further control untrusted SQL.  The size of the database
       
  2707 ** created by an untrusted script can be contained using the
       
  2708 ** [max_page_count] [PRAGMA].
       
  2709 **
       
  2710 ** New run-time limit categories may be added in future releases.
       
  2711 */
       
  2712 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
       
  2713 
       
  2714 /*
       
  2715 ** CAPI3REF: Run-Time Limit Categories
       
  2716 ** KEYWORDS: {limit category} {*limit categories}
       
  2717 **
       
  2718 ** These constants define various performance limits
       
  2719 ** that can be lowered at run-time using [sqlite3_limit()].
       
  2720 ** The synopsis of the meanings of the various limits is shown below.
       
  2721 ** Additional information is available at [limits | Limits in SQLite].
       
  2722 **
       
  2723 ** <dl>
       
  2724 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
       
  2725 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
       
  2726 **
       
  2727 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
       
  2728 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
       
  2729 **
       
  2730 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
       
  2731 ** <dd>The maximum number of columns in a table definition or in the
       
  2732 ** result set of a [SELECT] or the maximum number of columns in an index
       
  2733 ** or in an ORDER BY or GROUP BY clause.</dd>)^
       
  2734 **
       
  2735 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
       
  2736 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
       
  2737 **
       
  2738 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
       
  2739 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
       
  2740 **
       
  2741 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
       
  2742 ** <dd>The maximum number of instructions in a virtual machine program
       
  2743 ** used to implement an SQL statement.  This limit is not currently
       
  2744 ** enforced, though that might be added in some future release of
       
  2745 ** SQLite.</dd>)^
       
  2746 **
       
  2747 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
       
  2748 ** <dd>The maximum number of arguments on a function.</dd>)^
       
  2749 **
       
  2750 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
       
  2751 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
       
  2752 **
       
  2753 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
       
  2754 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
       
  2755 ** <dd>The maximum length of the pattern argument to the [LIKE] or
       
  2756 ** [GLOB] operators.</dd>)^
       
  2757 **
       
  2758 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
       
  2759 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
       
  2760 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
       
  2761 **
       
  2762 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
       
  2763 ** <dd>The maximum depth of recursion for triggers.</dd>)^
       
  2764 ** </dl>
       
  2765 */
       
  2766 #define SQLITE_LIMIT_LENGTH                    0
       
  2767 #define SQLITE_LIMIT_SQL_LENGTH                1
       
  2768 #define SQLITE_LIMIT_COLUMN                    2
       
  2769 #define SQLITE_LIMIT_EXPR_DEPTH                3
       
  2770 #define SQLITE_LIMIT_COMPOUND_SELECT           4
       
  2771 #define SQLITE_LIMIT_VDBE_OP                   5
       
  2772 #define SQLITE_LIMIT_FUNCTION_ARG              6
       
  2773 #define SQLITE_LIMIT_ATTACHED                  7
       
  2774 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
       
  2775 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
       
  2776 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
       
  2777 
       
  2778 /*
       
  2779 ** CAPI3REF: Compiling An SQL Statement
       
  2780 ** KEYWORDS: {SQL statement compiler}
       
  2781 **
       
  2782 ** To execute an SQL query, it must first be compiled into a byte-code
       
  2783 ** program using one of these routines.
       
  2784 **
       
  2785 ** The first argument, "db", is a [database connection] obtained from a
       
  2786 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
       
  2787 ** [sqlite3_open16()].  The database connection must not have been closed.
       
  2788 **
       
  2789 ** The second argument, "zSql", is the statement to be compiled, encoded
       
  2790 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
       
  2791 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
       
  2792 ** use UTF-16.
       
  2793 **
       
  2794 ** ^If the nByte argument is less than zero, then zSql is read up to the
       
  2795 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
       
  2796 ** number of  bytes read from zSql.  ^When nByte is non-negative, the
       
  2797 ** zSql string ends at either the first '\000' or '\u0000' character or
       
  2798 ** the nByte-th byte, whichever comes first. If the caller knows
       
  2799 ** that the supplied string is nul-terminated, then there is a small
       
  2800 ** performance advantage to be gained by passing an nByte parameter that
       
  2801 ** is equal to the number of bytes in the input string <i>including</i>
       
  2802 ** the nul-terminator bytes.
       
  2803 **
       
  2804 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
       
  2805 ** past the end of the first SQL statement in zSql.  These routines only
       
  2806 ** compile the first statement in zSql, so *pzTail is left pointing to
       
  2807 ** what remains uncompiled.
       
  2808 **
       
  2809 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
       
  2810 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
       
  2811 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
       
  2812 ** string or a comment) then *ppStmt is set to NULL.
       
  2813 ** The calling procedure is responsible for deleting the compiled
       
  2814 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
       
  2815 ** ppStmt may not be NULL.
       
  2816 **
       
  2817 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
       
  2818 ** otherwise an [error code] is returned.
       
  2819 **
       
  2820 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
       
  2821 ** recommended for all new programs. The two older interfaces are retained
       
  2822 ** for backwards compatibility, but their use is discouraged.
       
  2823 ** ^In the "v2" interfaces, the prepared statement
       
  2824 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
       
  2825 ** original SQL text. This causes the [sqlite3_step()] interface to
       
  2826 ** behave differently in three ways:
       
  2827 **
       
  2828 ** <ol>
       
  2829 ** <li>
       
  2830 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
       
  2831 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
       
  2832 ** statement and try to run it again.
       
  2833 ** </li>
       
  2834 **
       
  2835 ** <li>
       
  2836 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
       
  2837 ** [error codes] or [extended error codes].  ^The legacy behavior was that
       
  2838 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
       
  2839 ** and the application would have to make a second call to [sqlite3_reset()]
       
  2840 ** in order to find the underlying cause of the problem. With the "v2" prepare
       
  2841 ** interfaces, the underlying reason for the error is returned immediately.
       
  2842 ** </li>
       
  2843 **
       
  2844 ** <li>
       
  2845 ** ^If the specific value bound to [parameter | host parameter] in the 
       
  2846 ** WHERE clause might influence the choice of query plan for a statement,
       
  2847 ** then the statement will be automatically recompiled, as if there had been 
       
  2848 ** a schema change, on the first  [sqlite3_step()] call following any change
       
  2849 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 
       
  2850 ** ^The specific value of WHERE-clause [parameter] might influence the 
       
  2851 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
       
  2852 ** or [GLOB] operator or if the parameter is compared to an indexed column
       
  2853 ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled.
       
  2854 ** the 
       
  2855 ** </li>
       
  2856 ** </ol>
       
  2857 */
       
  2858 SQLITE_API int sqlite3_prepare(
       
  2859   sqlite3 *db,            /* Database handle */
       
  2860   const char *zSql,       /* SQL statement, UTF-8 encoded */
       
  2861   int nByte,              /* Maximum length of zSql in bytes. */
       
  2862   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2863   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2864 );
       
  2865 SQLITE_API int sqlite3_prepare_v2(
       
  2866   sqlite3 *db,            /* Database handle */
       
  2867   const char *zSql,       /* SQL statement, UTF-8 encoded */
       
  2868   int nByte,              /* Maximum length of zSql in bytes. */
       
  2869   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2870   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2871 );
       
  2872 SQLITE_API int sqlite3_prepare16(
       
  2873   sqlite3 *db,            /* Database handle */
       
  2874   const void *zSql,       /* SQL statement, UTF-16 encoded */
       
  2875   int nByte,              /* Maximum length of zSql in bytes. */
       
  2876   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2877   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2878 );
       
  2879 SQLITE_API int sqlite3_prepare16_v2(
       
  2880   sqlite3 *db,            /* Database handle */
       
  2881   const void *zSql,       /* SQL statement, UTF-16 encoded */
       
  2882   int nByte,              /* Maximum length of zSql in bytes. */
       
  2883   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2884   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2885 );
       
  2886 
       
  2887 /*
       
  2888 ** CAPI3REF: Retrieving Statement SQL
       
  2889 **
       
  2890 ** ^This interface can be used to retrieve a saved copy of the original
       
  2891 ** SQL text used to create a [prepared statement] if that statement was
       
  2892 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
       
  2893 */
       
  2894 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
       
  2895 
       
  2896 /*
       
  2897 ** CAPI3REF: Determine If An SQL Statement Writes The Database
       
  2898 **
       
  2899 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
       
  2900 ** and only if the [prepared statement] X makes no direct changes to
       
  2901 ** the content of the database file.
       
  2902 **
       
  2903 ** Note that [application-defined SQL functions] or
       
  2904 ** [virtual tables] might change the database indirectly as a side effect.  
       
  2905 ** ^(For example, if an application defines a function "eval()" that 
       
  2906 ** calls [sqlite3_exec()], then the following SQL statement would
       
  2907 ** change the database file through side-effects:
       
  2908 **
       
  2909 ** <blockquote><pre>
       
  2910 **    SELECT eval('DELETE FROM t1') FROM t2;
       
  2911 ** </pre></blockquote>
       
  2912 **
       
  2913 ** But because the [SELECT] statement does not change the database file
       
  2914 ** directly, sqlite3_stmt_readonly() would still return true.)^
       
  2915 **
       
  2916 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
       
  2917 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
       
  2918 ** since the statements themselves do not actually modify the database but
       
  2919 ** rather they control the timing of when other statements modify the 
       
  2920 ** database.  ^The [ATTACH] and [DETACH] statements also cause
       
  2921 ** sqlite3_stmt_readonly() to return true since, while those statements
       
  2922 ** change the configuration of a database connection, they do not make 
       
  2923 ** changes to the content of the database files on disk.
       
  2924 */
       
  2925 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
       
  2926 
       
  2927 /*
       
  2928 ** CAPI3REF: Dynamically Typed Value Object
       
  2929 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
       
  2930 **
       
  2931 ** SQLite uses the sqlite3_value object to represent all values
       
  2932 ** that can be stored in a database table. SQLite uses dynamic typing
       
  2933 ** for the values it stores.  ^Values stored in sqlite3_value objects
       
  2934 ** can be integers, floating point values, strings, BLOBs, or NULL.
       
  2935 **
       
  2936 ** An sqlite3_value object may be either "protected" or "unprotected".
       
  2937 ** Some interfaces require a protected sqlite3_value.  Other interfaces
       
  2938 ** will accept either a protected or an unprotected sqlite3_value.
       
  2939 ** Every interface that accepts sqlite3_value arguments specifies
       
  2940 ** whether or not it requires a protected sqlite3_value.
       
  2941 **
       
  2942 ** The terms "protected" and "unprotected" refer to whether or not
       
  2943 ** a mutex is held.  An internal mutex is held for a protected
       
  2944 ** sqlite3_value object but no mutex is held for an unprotected
       
  2945 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
       
  2946 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
       
  2947 ** or if SQLite is run in one of reduced mutex modes 
       
  2948 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
       
  2949 ** then there is no distinction between protected and unprotected
       
  2950 ** sqlite3_value objects and they can be used interchangeably.  However,
       
  2951 ** for maximum code portability it is recommended that applications
       
  2952 ** still make the distinction between protected and unprotected
       
  2953 ** sqlite3_value objects even when not strictly required.
       
  2954 **
       
  2955 ** ^The sqlite3_value objects that are passed as parameters into the
       
  2956 ** implementation of [application-defined SQL functions] are protected.
       
  2957 ** ^The sqlite3_value object returned by
       
  2958 ** [sqlite3_column_value()] is unprotected.
       
  2959 ** Unprotected sqlite3_value objects may only be used with
       
  2960 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
       
  2961 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
       
  2962 ** interfaces require protected sqlite3_value objects.
       
  2963 */
       
  2964 typedef struct Mem sqlite3_value;
       
  2965 
       
  2966 /*
       
  2967 ** CAPI3REF: SQL Function Context Object
       
  2968 **
       
  2969 ** The context in which an SQL function executes is stored in an
       
  2970 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
       
  2971 ** is always first parameter to [application-defined SQL functions].
       
  2972 ** The application-defined SQL function implementation will pass this
       
  2973 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
       
  2974 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
       
  2975 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
       
  2976 ** and/or [sqlite3_set_auxdata()].
       
  2977 */
       
  2978 typedef struct sqlite3_context sqlite3_context;
       
  2979 
       
  2980 /*
       
  2981 ** CAPI3REF: Binding Values To Prepared Statements
       
  2982 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
       
  2983 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
       
  2984 **
       
  2985 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
       
  2986 ** literals may be replaced by a [parameter] that matches one of following
       
  2987 ** templates:
       
  2988 **
       
  2989 ** <ul>
       
  2990 ** <li>  ?
       
  2991 ** <li>  ?NNN
       
  2992 ** <li>  :VVV
       
  2993 ** <li>  @VVV
       
  2994 ** <li>  $VVV
       
  2995 ** </ul>
       
  2996 **
       
  2997 ** In the templates above, NNN represents an integer literal,
       
  2998 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
       
  2999 ** parameters (also called "host parameter names" or "SQL parameters")
       
  3000 ** can be set using the sqlite3_bind_*() routines defined here.
       
  3001 **
       
  3002 ** ^The first argument to the sqlite3_bind_*() routines is always
       
  3003 ** a pointer to the [sqlite3_stmt] object returned from
       
  3004 ** [sqlite3_prepare_v2()] or its variants.
       
  3005 **
       
  3006 ** ^The second argument is the index of the SQL parameter to be set.
       
  3007 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
       
  3008 ** SQL parameter is used more than once, second and subsequent
       
  3009 ** occurrences have the same index as the first occurrence.
       
  3010 ** ^The index for named parameters can be looked up using the
       
  3011 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
       
  3012 ** for "?NNN" parameters is the value of NNN.
       
  3013 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
       
  3014 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
       
  3015 **
       
  3016 ** ^The third argument is the value to bind to the parameter.
       
  3017 **
       
  3018 ** ^(In those routines that have a fourth argument, its value is the
       
  3019 ** number of bytes in the parameter.  To be clear: the value is the
       
  3020 ** number of <u>bytes</u> in the value, not the number of characters.)^
       
  3021 ** ^If the fourth parameter is negative, the length of the string is
       
  3022 ** the number of bytes up to the first zero terminator.
       
  3023 **
       
  3024 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
       
  3025 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
       
  3026 ** string after SQLite has finished with it.  ^The destructor is called
       
  3027 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
       
  3028 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.  
       
  3029 ** ^If the fifth argument is
       
  3030 ** the special value [SQLITE_STATIC], then SQLite assumes that the
       
  3031 ** information is in static, unmanaged space and does not need to be freed.
       
  3032 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
       
  3033 ** SQLite makes its own private copy of the data immediately, before
       
  3034 ** the sqlite3_bind_*() routine returns.
       
  3035 **
       
  3036 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
       
  3037 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
       
  3038 ** (just an integer to hold its size) while it is being processed.
       
  3039 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
       
  3040 ** content is later written using
       
  3041 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
       
  3042 ** ^A negative value for the zeroblob results in a zero-length BLOB.
       
  3043 **
       
  3044 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
       
  3045 ** for the [prepared statement] or with a prepared statement for which
       
  3046 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
       
  3047 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
       
  3048 ** routine is passed a [prepared statement] that has been finalized, the
       
  3049 ** result is undefined and probably harmful.
       
  3050 **
       
  3051 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
       
  3052 ** ^Unbound parameters are interpreted as NULL.
       
  3053 **
       
  3054 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
       
  3055 ** [error code] if anything goes wrong.
       
  3056 ** ^[SQLITE_RANGE] is returned if the parameter
       
  3057 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
       
  3058 **
       
  3059 ** See also: [sqlite3_bind_parameter_count()],
       
  3060 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
       
  3061 */
       
  3062 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
       
  3063 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
       
  3064 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
       
  3065 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
       
  3066 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
       
  3067 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
       
  3068 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
       
  3069 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
       
  3070 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
       
  3071 
       
  3072 /*
       
  3073 ** CAPI3REF: Number Of SQL Parameters
       
  3074 **
       
  3075 ** ^This routine can be used to find the number of [SQL parameters]
       
  3076 ** in a [prepared statement].  SQL parameters are tokens of the
       
  3077 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
       
  3078 ** placeholders for values that are [sqlite3_bind_blob | bound]
       
  3079 ** to the parameters at a later time.
       
  3080 **
       
  3081 ** ^(This routine actually returns the index of the largest (rightmost)
       
  3082 ** parameter. For all forms except ?NNN, this will correspond to the
       
  3083 ** number of unique parameters.  If parameters of the ?NNN form are used,
       
  3084 ** there may be gaps in the list.)^
       
  3085 **
       
  3086 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  3087 ** [sqlite3_bind_parameter_name()], and
       
  3088 ** [sqlite3_bind_parameter_index()].
       
  3089 */
       
  3090 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
       
  3091 
       
  3092 /*
       
  3093 ** CAPI3REF: Name Of A Host Parameter
       
  3094 **
       
  3095 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
       
  3096 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
       
  3097 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
       
  3098 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
       
  3099 ** respectively.
       
  3100 ** In other words, the initial ":" or "$" or "@" or "?"
       
  3101 ** is included as part of the name.)^
       
  3102 ** ^Parameters of the form "?" without a following integer have no name
       
  3103 ** and are referred to as "nameless" or "anonymous parameters".
       
  3104 **
       
  3105 ** ^The first host parameter has an index of 1, not 0.
       
  3106 **
       
  3107 ** ^If the value N is out of range or if the N-th parameter is
       
  3108 ** nameless, then NULL is returned.  ^The returned string is
       
  3109 ** always in UTF-8 encoding even if the named parameter was
       
  3110 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
       
  3111 ** [sqlite3_prepare16_v2()].
       
  3112 **
       
  3113 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  3114 ** [sqlite3_bind_parameter_count()], and
       
  3115 ** [sqlite3_bind_parameter_index()].
       
  3116 */
       
  3117 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
       
  3118 
       
  3119 /*
       
  3120 ** CAPI3REF: Index Of A Parameter With A Given Name
       
  3121 **
       
  3122 ** ^Return the index of an SQL parameter given its name.  ^The
       
  3123 ** index value returned is suitable for use as the second
       
  3124 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
       
  3125 ** is returned if no matching parameter is found.  ^The parameter
       
  3126 ** name must be given in UTF-8 even if the original statement
       
  3127 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
       
  3128 **
       
  3129 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  3130 ** [sqlite3_bind_parameter_count()], and
       
  3131 ** [sqlite3_bind_parameter_index()].
       
  3132 */
       
  3133 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
       
  3134 
       
  3135 /*
       
  3136 ** CAPI3REF: Reset All Bindings On A Prepared Statement
       
  3137 **
       
  3138 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
       
  3139 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
       
  3140 ** ^Use this routine to reset all host parameters to NULL.
       
  3141 */
       
  3142 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
       
  3143 
       
  3144 /*
       
  3145 ** CAPI3REF: Number Of Columns In A Result Set
       
  3146 **
       
  3147 ** ^Return the number of columns in the result set returned by the
       
  3148 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
       
  3149 ** statement that does not return data (for example an [UPDATE]).
       
  3150 **
       
  3151 ** See also: [sqlite3_data_count()]
       
  3152 */
       
  3153 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
       
  3154 
       
  3155 /*
       
  3156 ** CAPI3REF: Column Names In A Result Set
       
  3157 **
       
  3158 ** ^These routines return the name assigned to a particular column
       
  3159 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
       
  3160 ** interface returns a pointer to a zero-terminated UTF-8 string
       
  3161 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
       
  3162 ** UTF-16 string.  ^The first parameter is the [prepared statement]
       
  3163 ** that implements the [SELECT] statement. ^The second parameter is the
       
  3164 ** column number.  ^The leftmost column is number 0.
       
  3165 **
       
  3166 ** ^The returned string pointer is valid until either the [prepared statement]
       
  3167 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
       
  3168 ** reprepared by the first call to [sqlite3_step()] for a particular run
       
  3169 ** or until the next call to
       
  3170 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
       
  3171 **
       
  3172 ** ^If sqlite3_malloc() fails during the processing of either routine
       
  3173 ** (for example during a conversion from UTF-8 to UTF-16) then a
       
  3174 ** NULL pointer is returned.
       
  3175 **
       
  3176 ** ^The name of a result column is the value of the "AS" clause for
       
  3177 ** that column, if there is an AS clause.  If there is no AS clause
       
  3178 ** then the name of the column is unspecified and may change from
       
  3179 ** one release of SQLite to the next.
       
  3180 */
       
  3181 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
       
  3182 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
       
  3183 
       
  3184 /*
       
  3185 ** CAPI3REF: Source Of Data In A Query Result
       
  3186 **
       
  3187 ** ^These routines provide a means to determine the database, table, and
       
  3188 ** table column that is the origin of a particular result column in
       
  3189 ** [SELECT] statement.
       
  3190 ** ^The name of the database or table or column can be returned as
       
  3191 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
       
  3192 ** the database name, the _table_ routines return the table name, and
       
  3193 ** the origin_ routines return the column name.
       
  3194 ** ^The returned string is valid until the [prepared statement] is destroyed
       
  3195 ** using [sqlite3_finalize()] or until the statement is automatically
       
  3196 ** reprepared by the first call to [sqlite3_step()] for a particular run
       
  3197 ** or until the same information is requested
       
  3198 ** again in a different encoding.
       
  3199 **
       
  3200 ** ^The names returned are the original un-aliased names of the
       
  3201 ** database, table, and column.
       
  3202 **
       
  3203 ** ^The first argument to these interfaces is a [prepared statement].
       
  3204 ** ^These functions return information about the Nth result column returned by
       
  3205 ** the statement, where N is the second function argument.
       
  3206 ** ^The left-most column is column 0 for these routines.
       
  3207 **
       
  3208 ** ^If the Nth column returned by the statement is an expression or
       
  3209 ** subquery and is not a column value, then all of these functions return
       
  3210 ** NULL.  ^These routine might also return NULL if a memory allocation error
       
  3211 ** occurs.  ^Otherwise, they return the name of the attached database, table,
       
  3212 ** or column that query result column was extracted from.
       
  3213 **
       
  3214 ** ^As with all other SQLite APIs, those whose names end with "16" return
       
  3215 ** UTF-16 encoded strings and the other functions return UTF-8.
       
  3216 **
       
  3217 ** ^These APIs are only available if the library was compiled with the
       
  3218 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
       
  3219 **
       
  3220 ** If two or more threads call one or more of these routines against the same
       
  3221 ** prepared statement and column at the same time then the results are
       
  3222 ** undefined.
       
  3223 **
       
  3224 ** If two or more threads call one or more
       
  3225 ** [sqlite3_column_database_name | column metadata interfaces]
       
  3226 ** for the same [prepared statement] and result column
       
  3227 ** at the same time then the results are undefined.
       
  3228 */
       
  3229 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
       
  3230 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
       
  3231 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
       
  3232 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
       
  3233 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
       
  3234 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
       
  3235 
       
  3236 /*
       
  3237 ** CAPI3REF: Declared Datatype Of A Query Result
       
  3238 **
       
  3239 ** ^(The first parameter is a [prepared statement].
       
  3240 ** If this statement is a [SELECT] statement and the Nth column of the
       
  3241 ** returned result set of that [SELECT] is a table column (not an
       
  3242 ** expression or subquery) then the declared type of the table
       
  3243 ** column is returned.)^  ^If the Nth column of the result set is an
       
  3244 ** expression or subquery, then a NULL pointer is returned.
       
  3245 ** ^The returned string is always UTF-8 encoded.
       
  3246 **
       
  3247 ** ^(For example, given the database schema:
       
  3248 **
       
  3249 ** CREATE TABLE t1(c1 VARIANT);
       
  3250 **
       
  3251 ** and the following statement to be compiled:
       
  3252 **
       
  3253 ** SELECT c1 + 1, c1 FROM t1;
       
  3254 **
       
  3255 ** this routine would return the string "VARIANT" for the second result
       
  3256 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
       
  3257 **
       
  3258 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
       
  3259 ** is declared to contain a particular type does not mean that the
       
  3260 ** data stored in that column is of the declared type.  SQLite is
       
  3261 ** strongly typed, but the typing is dynamic not static.  ^Type
       
  3262 ** is associated with individual values, not with the containers
       
  3263 ** used to hold those values.
       
  3264 */
       
  3265 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
       
  3266 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
       
  3267 
       
  3268 /*
       
  3269 ** CAPI3REF: Evaluate An SQL Statement
       
  3270 **
       
  3271 ** After a [prepared statement] has been prepared using either
       
  3272 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
       
  3273 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
       
  3274 ** must be called one or more times to evaluate the statement.
       
  3275 **
       
  3276 ** The details of the behavior of the sqlite3_step() interface depend
       
  3277 ** on whether the statement was prepared using the newer "v2" interface
       
  3278 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
       
  3279 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
       
  3280 ** new "v2" interface is recommended for new applications but the legacy
       
  3281 ** interface will continue to be supported.
       
  3282 **
       
  3283 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
       
  3284 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
       
  3285 ** ^With the "v2" interface, any of the other [result codes] or
       
  3286 ** [extended result codes] might be returned as well.
       
  3287 **
       
  3288 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
       
  3289 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
       
  3290 ** or occurs outside of an explicit transaction, then you can retry the
       
  3291 ** statement.  If the statement is not a [COMMIT] and occurs within an
       
  3292 ** explicit transaction then you should rollback the transaction before
       
  3293 ** continuing.
       
  3294 **
       
  3295 ** ^[SQLITE_DONE] means that the statement has finished executing
       
  3296 ** successfully.  sqlite3_step() should not be called again on this virtual
       
  3297 ** machine without first calling [sqlite3_reset()] to reset the virtual
       
  3298 ** machine back to its initial state.
       
  3299 **
       
  3300 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
       
  3301 ** is returned each time a new row of data is ready for processing by the
       
  3302 ** caller. The values may be accessed using the [column access functions].
       
  3303 ** sqlite3_step() is called again to retrieve the next row of data.
       
  3304 **
       
  3305 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
       
  3306 ** violation) has occurred.  sqlite3_step() should not be called again on
       
  3307 ** the VM. More information may be found by calling [sqlite3_errmsg()].
       
  3308 ** ^With the legacy interface, a more specific error code (for example,
       
  3309 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
       
  3310 ** can be obtained by calling [sqlite3_reset()] on the
       
  3311 ** [prepared statement].  ^In the "v2" interface,
       
  3312 ** the more specific error code is returned directly by sqlite3_step().
       
  3313 **
       
  3314 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
       
  3315 ** Perhaps it was called on a [prepared statement] that has
       
  3316 ** already been [sqlite3_finalize | finalized] or on one that had
       
  3317 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
       
  3318 ** be the case that the same database connection is being used by two or
       
  3319 ** more threads at the same moment in time.
       
  3320 **
       
  3321 ** For all versions of SQLite up to and including 3.6.23.1, a call to
       
  3322 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
       
  3323 ** other than [SQLITE_ROW] before any subsequent invocation of
       
  3324 ** sqlite3_step().  Failure to reset the prepared statement using 
       
  3325 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
       
  3326 ** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
       
  3327 ** calling [sqlite3_reset()] automatically in this circumstance rather
       
  3328 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
       
  3329 ** break because any application that ever receives an SQLITE_MISUSE error
       
  3330 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
       
  3331 ** can be used to restore the legacy behavior.
       
  3332 **
       
  3333 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
       
  3334 ** API always returns a generic error code, [SQLITE_ERROR], following any
       
  3335 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
       
  3336 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
       
  3337 ** specific [error codes] that better describes the error.
       
  3338 ** We admit that this is a goofy design.  The problem has been fixed
       
  3339 ** with the "v2" interface.  If you prepare all of your SQL statements
       
  3340 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
       
  3341 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
       
  3342 ** then the more specific [error codes] are returned directly
       
  3343 ** by sqlite3_step().  The use of the "v2" interface is recommended.
       
  3344 */
       
  3345 SQLITE_API int sqlite3_step(sqlite3_stmt*);
       
  3346 
       
  3347 /*
       
  3348 ** CAPI3REF: Number of columns in a result set
       
  3349 **
       
  3350 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
       
  3351 ** current row of the result set of [prepared statement] P.
       
  3352 ** ^If prepared statement P does not have results ready to return
       
  3353 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
       
  3354 ** interfaces) then sqlite3_data_count(P) returns 0.
       
  3355 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
       
  3356 **
       
  3357 ** See also: [sqlite3_column_count()]
       
  3358 */
       
  3359 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
       
  3360 
       
  3361 /*
       
  3362 ** CAPI3REF: Fundamental Datatypes
       
  3363 ** KEYWORDS: SQLITE_TEXT
       
  3364 **
       
  3365 ** ^(Every value in SQLite has one of five fundamental datatypes:
       
  3366 **
       
  3367 ** <ul>
       
  3368 ** <li> 64-bit signed integer
       
  3369 ** <li> 64-bit IEEE floating point number
       
  3370 ** <li> string
       
  3371 ** <li> BLOB
       
  3372 ** <li> NULL
       
  3373 ** </ul>)^
       
  3374 **
       
  3375 ** These constants are codes for each of those types.
       
  3376 **
       
  3377 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
       
  3378 ** for a completely different meaning.  Software that links against both
       
  3379 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
       
  3380 ** SQLITE_TEXT.
       
  3381 */
       
  3382 #define SQLITE_INTEGER  1
       
  3383 #define SQLITE_FLOAT    2
       
  3384 #define SQLITE_BLOB     4
       
  3385 #define SQLITE_NULL     5
       
  3386 #ifdef SQLITE_TEXT
       
  3387 # undef SQLITE_TEXT
       
  3388 #else
       
  3389 # define SQLITE_TEXT     3
       
  3390 #endif
       
  3391 #define SQLITE3_TEXT     3
       
  3392 
       
  3393 /*
       
  3394 ** CAPI3REF: Result Values From A Query
       
  3395 ** KEYWORDS: {column access functions}
       
  3396 **
       
  3397 ** These routines form the "result set" interface.
       
  3398 **
       
  3399 ** ^These routines return information about a single column of the current
       
  3400 ** result row of a query.  ^In every case the first argument is a pointer
       
  3401 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
       
  3402 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
       
  3403 ** and the second argument is the index of the column for which information
       
  3404 ** should be returned. ^The leftmost column of the result set has the index 0.
       
  3405 ** ^The number of columns in the result can be determined using
       
  3406 ** [sqlite3_column_count()].
       
  3407 **
       
  3408 ** If the SQL statement does not currently point to a valid row, or if the
       
  3409 ** column index is out of range, the result is undefined.
       
  3410 ** These routines may only be called when the most recent call to
       
  3411 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
       
  3412 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
       
  3413 ** If any of these routines are called after [sqlite3_reset()] or
       
  3414 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
       
  3415 ** something other than [SQLITE_ROW], the results are undefined.
       
  3416 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
       
  3417 ** are called from a different thread while any of these routines
       
  3418 ** are pending, then the results are undefined.
       
  3419 **
       
  3420 ** ^The sqlite3_column_type() routine returns the
       
  3421 ** [SQLITE_INTEGER | datatype code] for the initial data type
       
  3422 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
       
  3423 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
       
  3424 ** returned by sqlite3_column_type() is only meaningful if no type
       
  3425 ** conversions have occurred as described below.  After a type conversion,
       
  3426 ** the value returned by sqlite3_column_type() is undefined.  Future
       
  3427 ** versions of SQLite may change the behavior of sqlite3_column_type()
       
  3428 ** following a type conversion.
       
  3429 **
       
  3430 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
       
  3431 ** routine returns the number of bytes in that BLOB or string.
       
  3432 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
       
  3433 ** the string to UTF-8 and then returns the number of bytes.
       
  3434 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
       
  3435 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
       
  3436 ** the number of bytes in that string.
       
  3437 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
       
  3438 **
       
  3439 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
       
  3440 ** routine returns the number of bytes in that BLOB or string.
       
  3441 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
       
  3442 ** the string to UTF-16 and then returns the number of bytes.
       
  3443 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
       
  3444 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
       
  3445 ** the number of bytes in that string.
       
  3446 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
       
  3447 **
       
  3448 ** ^The values returned by [sqlite3_column_bytes()] and 
       
  3449 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
       
  3450 ** of the string.  ^For clarity: the values returned by
       
  3451 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
       
  3452 ** bytes in the string, not the number of characters.
       
  3453 **
       
  3454 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
       
  3455 ** even empty strings, are always zero terminated.  ^The return
       
  3456 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
       
  3457 **
       
  3458 ** ^The object returned by [sqlite3_column_value()] is an
       
  3459 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
       
  3460 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
       
  3461 ** If the [unprotected sqlite3_value] object returned by
       
  3462 ** [sqlite3_column_value()] is used in any other way, including calls
       
  3463 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
       
  3464 ** or [sqlite3_value_bytes()], then the behavior is undefined.
       
  3465 **
       
  3466 ** These routines attempt to convert the value where appropriate.  ^For
       
  3467 ** example, if the internal representation is FLOAT and a text result
       
  3468 ** is requested, [sqlite3_snprintf()] is used internally to perform the
       
  3469 ** conversion automatically.  ^(The following table details the conversions
       
  3470 ** that are applied:
       
  3471 **
       
  3472 ** <blockquote>
       
  3473 ** <table border="1">
       
  3474 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
       
  3475 **
       
  3476 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
       
  3477 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
       
  3478 ** <tr><td>  NULL    <td>   TEXT    <td> Result is NULL pointer
       
  3479 ** <tr><td>  NULL    <td>   BLOB    <td> Result is NULL pointer
       
  3480 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
       
  3481 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
       
  3482 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
       
  3483 ** <tr><td>  FLOAT   <td> INTEGER   <td> Convert from float to integer
       
  3484 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
       
  3485 ** <tr><td>  FLOAT   <td>   BLOB    <td> Same as FLOAT->TEXT
       
  3486 ** <tr><td>  TEXT    <td> INTEGER   <td> Use atoi()
       
  3487 ** <tr><td>  TEXT    <td>  FLOAT    <td> Use atof()
       
  3488 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
       
  3489 ** <tr><td>  BLOB    <td> INTEGER   <td> Convert to TEXT then use atoi()
       
  3490 ** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
       
  3491 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
       
  3492 ** </table>
       
  3493 ** </blockquote>)^
       
  3494 **
       
  3495 ** The table above makes reference to standard C library functions atoi()
       
  3496 ** and atof().  SQLite does not really use these functions.  It has its
       
  3497 ** own equivalent internal routines.  The atoi() and atof() names are
       
  3498 ** used in the table for brevity and because they are familiar to most
       
  3499 ** C programmers.
       
  3500 **
       
  3501 ** Note that when type conversions occur, pointers returned by prior
       
  3502 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
       
  3503 ** sqlite3_column_text16() may be invalidated.
       
  3504 ** Type conversions and pointer invalidations might occur
       
  3505 ** in the following cases:
       
  3506 **
       
  3507 ** <ul>
       
  3508 ** <li> The initial content is a BLOB and sqlite3_column_text() or
       
  3509 **      sqlite3_column_text16() is called.  A zero-terminator might
       
  3510 **      need to be added to the string.</li>
       
  3511 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
       
  3512 **      sqlite3_column_text16() is called.  The content must be converted
       
  3513 **      to UTF-16.</li>
       
  3514 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
       
  3515 **      sqlite3_column_text() is called.  The content must be converted
       
  3516 **      to UTF-8.</li>
       
  3517 ** </ul>
       
  3518 **
       
  3519 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
       
  3520 ** not invalidate a prior pointer, though of course the content of the buffer
       
  3521 ** that the prior pointer references will have been modified.  Other kinds
       
  3522 ** of conversion are done in place when it is possible, but sometimes they
       
  3523 ** are not possible and in those cases prior pointers are invalidated.
       
  3524 **
       
  3525 ** The safest and easiest to remember policy is to invoke these routines
       
  3526 ** in one of the following ways:
       
  3527 **
       
  3528 ** <ul>
       
  3529 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
       
  3530 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
       
  3531 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
       
  3532 ** </ul>
       
  3533 **
       
  3534 ** In other words, you should call sqlite3_column_text(),
       
  3535 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
       
  3536 ** into the desired format, then invoke sqlite3_column_bytes() or
       
  3537 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
       
  3538 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
       
  3539 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
       
  3540 ** with calls to sqlite3_column_bytes().
       
  3541 **
       
  3542 ** ^The pointers returned are valid until a type conversion occurs as
       
  3543 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
       
  3544 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
       
  3545 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
       
  3546 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
       
  3547 ** [sqlite3_free()].
       
  3548 **
       
  3549 ** ^(If a memory allocation error occurs during the evaluation of any
       
  3550 ** of these routines, a default value is returned.  The default value
       
  3551 ** is either the integer 0, the floating point number 0.0, or a NULL
       
  3552 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
       
  3553 ** [SQLITE_NOMEM].)^
       
  3554 */
       
  3555 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
       
  3556 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
       
  3557 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
       
  3558 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
       
  3559 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
       
  3560 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
       
  3561 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
       
  3562 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
       
  3563 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
       
  3564 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
       
  3565 
       
  3566 /*
       
  3567 ** CAPI3REF: Destroy A Prepared Statement Object
       
  3568 **
       
  3569 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
       
  3570 ** ^If the most recent evaluation of the statement encountered no errors
       
  3571 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
       
  3572 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
       
  3573 ** sqlite3_finalize(S) returns the appropriate [error code] or
       
  3574 ** [extended error code].
       
  3575 **
       
  3576 ** ^The sqlite3_finalize(S) routine can be called at any point during
       
  3577 ** the life cycle of [prepared statement] S:
       
  3578 ** before statement S is ever evaluated, after
       
  3579 ** one or more calls to [sqlite3_reset()], or after any call
       
  3580 ** to [sqlite3_step()] regardless of whether or not the statement has
       
  3581 ** completed execution.
       
  3582 **
       
  3583 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
       
  3584 **
       
  3585 ** The application must finalize every [prepared statement] in order to avoid
       
  3586 ** resource leaks.  It is a grievous error for the application to try to use
       
  3587 ** a prepared statement after it has been finalized.  Any use of a prepared
       
  3588 ** statement after it has been finalized can result in undefined and
       
  3589 ** undesirable behavior such as segfaults and heap corruption.
       
  3590 */
       
  3591 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
       
  3592 
       
  3593 /*
       
  3594 ** CAPI3REF: Reset A Prepared Statement Object
       
  3595 **
       
  3596 ** The sqlite3_reset() function is called to reset a [prepared statement]
       
  3597 ** object back to its initial state, ready to be re-executed.
       
  3598 ** ^Any SQL statement variables that had values bound to them using
       
  3599 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
       
  3600 ** Use [sqlite3_clear_bindings()] to reset the bindings.
       
  3601 **
       
  3602 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
       
  3603 ** back to the beginning of its program.
       
  3604 **
       
  3605 ** ^If the most recent call to [sqlite3_step(S)] for the
       
  3606 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
       
  3607 ** or if [sqlite3_step(S)] has never before been called on S,
       
  3608 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
       
  3609 **
       
  3610 ** ^If the most recent call to [sqlite3_step(S)] for the
       
  3611 ** [prepared statement] S indicated an error, then
       
  3612 ** [sqlite3_reset(S)] returns an appropriate [error code].
       
  3613 **
       
  3614 ** ^The [sqlite3_reset(S)] interface does not change the values
       
  3615 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
       
  3616 */
       
  3617 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
       
  3618 
       
  3619 /*
       
  3620 ** CAPI3REF: Create Or Redefine SQL Functions
       
  3621 ** KEYWORDS: {function creation routines}
       
  3622 ** KEYWORDS: {application-defined SQL function}
       
  3623 ** KEYWORDS: {application-defined SQL functions}
       
  3624 **
       
  3625 ** ^These functions (collectively known as "function creation routines")
       
  3626 ** are used to add SQL functions or aggregates or to redefine the behavior
       
  3627 ** of existing SQL functions or aggregates.  The only differences between
       
  3628 ** these routines are the text encoding expected for
       
  3629 ** the second parameter (the name of the function being created)
       
  3630 ** and the presence or absence of a destructor callback for
       
  3631 ** the application data pointer.
       
  3632 **
       
  3633 ** ^The first parameter is the [database connection] to which the SQL
       
  3634 ** function is to be added.  ^If an application uses more than one database
       
  3635 ** connection then application-defined SQL functions must be added
       
  3636 ** to each database connection separately.
       
  3637 **
       
  3638 ** ^The second parameter is the name of the SQL function to be created or
       
  3639 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
       
  3640 ** representation, exclusive of the zero-terminator.  ^Note that the name
       
  3641 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.  
       
  3642 ** ^Any attempt to create a function with a longer name
       
  3643 ** will result in [SQLITE_MISUSE] being returned.
       
  3644 **
       
  3645 ** ^The third parameter (nArg)
       
  3646 ** is the number of arguments that the SQL function or
       
  3647 ** aggregate takes. ^If this parameter is -1, then the SQL function or
       
  3648 ** aggregate may take any number of arguments between 0 and the limit
       
  3649 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
       
  3650 ** parameter is less than -1 or greater than 127 then the behavior is
       
  3651 ** undefined.
       
  3652 **
       
  3653 ** ^The fourth parameter, eTextRep, specifies what
       
  3654 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
       
  3655 ** its parameters.  Every SQL function implementation must be able to work
       
  3656 ** with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
       
  3657 ** more efficient with one encoding than another.  ^An application may
       
  3658 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
       
  3659 ** times with the same function but with different values of eTextRep.
       
  3660 ** ^When multiple implementations of the same function are available, SQLite
       
  3661 ** will pick the one that involves the least amount of data conversion.
       
  3662 ** If there is only a single implementation which does not care what text
       
  3663 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
       
  3664 **
       
  3665 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
       
  3666 ** function can gain access to this pointer using [sqlite3_user_data()].)^
       
  3667 **
       
  3668 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
       
  3669 ** pointers to C-language functions that implement the SQL function or
       
  3670 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
       
  3671 ** callback only; NULL pointers must be passed as the xStep and xFinal
       
  3672 ** parameters. ^An aggregate SQL function requires an implementation of xStep
       
  3673 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
       
  3674 ** SQL function or aggregate, pass NULL pointers for all three function
       
  3675 ** callbacks.
       
  3676 **
       
  3677 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
       
  3678 ** then it is destructor for the application data pointer. 
       
  3679 ** The destructor is invoked when the function is deleted, either by being
       
  3680 ** overloaded or when the database connection closes.)^
       
  3681 ** ^The destructor is also invoked if the call to
       
  3682 ** sqlite3_create_function_v2() fails.
       
  3683 ** ^When the destructor callback of the tenth parameter is invoked, it
       
  3684 ** is passed a single argument which is a copy of the application data 
       
  3685 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
       
  3686 **
       
  3687 ** ^It is permitted to register multiple implementations of the same
       
  3688 ** functions with the same name but with either differing numbers of
       
  3689 ** arguments or differing preferred text encodings.  ^SQLite will use
       
  3690 ** the implementation that most closely matches the way in which the
       
  3691 ** SQL function is used.  ^A function implementation with a non-negative
       
  3692 ** nArg parameter is a better match than a function implementation with
       
  3693 ** a negative nArg.  ^A function where the preferred text encoding
       
  3694 ** matches the database encoding is a better
       
  3695 ** match than a function where the encoding is different.  
       
  3696 ** ^A function where the encoding difference is between UTF16le and UTF16be
       
  3697 ** is a closer match than a function where the encoding difference is
       
  3698 ** between UTF8 and UTF16.
       
  3699 **
       
  3700 ** ^Built-in functions may be overloaded by new application-defined functions.
       
  3701 **
       
  3702 ** ^An application-defined function is permitted to call other
       
  3703 ** SQLite interfaces.  However, such calls must not
       
  3704 ** close the database connection nor finalize or reset the prepared
       
  3705 ** statement in which the function is running.
       
  3706 */
       
  3707 SQLITE_API int sqlite3_create_function(
       
  3708   sqlite3 *db,
       
  3709   const char *zFunctionName,
       
  3710   int nArg,
       
  3711   int eTextRep,
       
  3712   void *pApp,
       
  3713   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3714   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3715   void (*xFinal)(sqlite3_context*)
       
  3716 );
       
  3717 SQLITE_API int sqlite3_create_function16(
       
  3718   sqlite3 *db,
       
  3719   const void *zFunctionName,
       
  3720   int nArg,
       
  3721   int eTextRep,
       
  3722   void *pApp,
       
  3723   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3724   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3725   void (*xFinal)(sqlite3_context*)
       
  3726 );
       
  3727 SQLITE_API int sqlite3_create_function_v2(
       
  3728   sqlite3 *db,
       
  3729   const char *zFunctionName,
       
  3730   int nArg,
       
  3731   int eTextRep,
       
  3732   void *pApp,
       
  3733   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3734   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3735   void (*xFinal)(sqlite3_context*),
       
  3736   void(*xDestroy)(void*)
       
  3737 );
       
  3738 
       
  3739 /*
       
  3740 ** CAPI3REF: Text Encodings
       
  3741 **
       
  3742 ** These constant define integer codes that represent the various
       
  3743 ** text encodings supported by SQLite.
       
  3744 */
       
  3745 #define SQLITE_UTF8           1
       
  3746 #define SQLITE_UTF16LE        2
       
  3747 #define SQLITE_UTF16BE        3
       
  3748 #define SQLITE_UTF16          4    /* Use native byte order */
       
  3749 #define SQLITE_ANY            5    /* sqlite3_create_function only */
       
  3750 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
       
  3751 
       
  3752 /*
       
  3753 ** CAPI3REF: Deprecated Functions
       
  3754 ** DEPRECATED
       
  3755 **
       
  3756 ** These functions are [deprecated].  In order to maintain
       
  3757 ** backwards compatibility with older code, these functions continue 
       
  3758 ** to be supported.  However, new applications should avoid
       
  3759 ** the use of these functions.  To help encourage people to avoid
       
  3760 ** using these functions, we are not going to tell you what they do.
       
  3761 */
       
  3762 #ifndef SQLITE_OMIT_DEPRECATED
       
  3763 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
       
  3764 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
       
  3765 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
       
  3766 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
       
  3767 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
       
  3768 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
       
  3769 #endif
       
  3770 
       
  3771 /*
       
  3772 ** CAPI3REF: Obtaining SQL Function Parameter Values
       
  3773 **
       
  3774 ** The C-language implementation of SQL functions and aggregates uses
       
  3775 ** this set of interface routines to access the parameter values on
       
  3776 ** the function or aggregate.
       
  3777 **
       
  3778 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
       
  3779 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
       
  3780 ** define callbacks that implement the SQL functions and aggregates.
       
  3781 ** The 3rd parameter to these callbacks is an array of pointers to
       
  3782 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
       
  3783 ** each parameter to the SQL function.  These routines are used to
       
  3784 ** extract values from the [sqlite3_value] objects.
       
  3785 **
       
  3786 ** These routines work only with [protected sqlite3_value] objects.
       
  3787 ** Any attempt to use these routines on an [unprotected sqlite3_value]
       
  3788 ** object results in undefined behavior.
       
  3789 **
       
  3790 ** ^These routines work just like the corresponding [column access functions]
       
  3791 ** except that  these routines take a single [protected sqlite3_value] object
       
  3792 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
       
  3793 **
       
  3794 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
       
  3795 ** in the native byte-order of the host machine.  ^The
       
  3796 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
       
  3797 ** extract UTF-16 strings as big-endian and little-endian respectively.
       
  3798 **
       
  3799 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
       
  3800 ** numeric affinity to the value.  This means that an attempt is
       
  3801 ** made to convert the value to an integer or floating point.  If
       
  3802 ** such a conversion is possible without loss of information (in other
       
  3803 ** words, if the value is a string that looks like a number)
       
  3804 ** then the conversion is performed.  Otherwise no conversion occurs.
       
  3805 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
       
  3806 **
       
  3807 ** Please pay particular attention to the fact that the pointer returned
       
  3808 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
       
  3809 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
       
  3810 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
       
  3811 ** or [sqlite3_value_text16()].
       
  3812 **
       
  3813 ** These routines must be called from the same thread as
       
  3814 ** the SQL function that supplied the [sqlite3_value*] parameters.
       
  3815 */
       
  3816 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
       
  3817 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
       
  3818 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
       
  3819 SQLITE_API double sqlite3_value_double(sqlite3_value*);
       
  3820 SQLITE_API int sqlite3_value_int(sqlite3_value*);
       
  3821 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
       
  3822 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
       
  3823 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
       
  3824 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
       
  3825 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
       
  3826 SQLITE_API int sqlite3_value_type(sqlite3_value*);
       
  3827 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
       
  3828 
       
  3829 /*
       
  3830 ** CAPI3REF: Obtain Aggregate Function Context
       
  3831 **
       
  3832 ** Implementations of aggregate SQL functions use this
       
  3833 ** routine to allocate memory for storing their state.
       
  3834 **
       
  3835 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 
       
  3836 ** for a particular aggregate function, SQLite
       
  3837 ** allocates N of memory, zeroes out that memory, and returns a pointer
       
  3838 ** to the new memory. ^On second and subsequent calls to
       
  3839 ** sqlite3_aggregate_context() for the same aggregate function instance,
       
  3840 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
       
  3841 ** called once for each invocation of the xStep callback and then one
       
  3842 ** last time when the xFinal callback is invoked.  ^(When no rows match
       
  3843 ** an aggregate query, the xStep() callback of the aggregate function
       
  3844 ** implementation is never called and xFinal() is called exactly once.
       
  3845 ** In those cases, sqlite3_aggregate_context() might be called for the
       
  3846 ** first time from within xFinal().)^
       
  3847 **
       
  3848 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
       
  3849 ** less than or equal to zero or if a memory allocate error occurs.
       
  3850 **
       
  3851 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
       
  3852 ** determined by the N parameter on first successful call.  Changing the
       
  3853 ** value of N in subsequent call to sqlite3_aggregate_context() within
       
  3854 ** the same aggregate function instance will not resize the memory
       
  3855 ** allocation.)^
       
  3856 **
       
  3857 ** ^SQLite automatically frees the memory allocated by 
       
  3858 ** sqlite3_aggregate_context() when the aggregate query concludes.
       
  3859 **
       
  3860 ** The first parameter must be a copy of the
       
  3861 ** [sqlite3_context | SQL function context] that is the first parameter
       
  3862 ** to the xStep or xFinal callback routine that implements the aggregate
       
  3863 ** function.
       
  3864 **
       
  3865 ** This routine must be called from the same thread in which
       
  3866 ** the aggregate SQL function is running.
       
  3867 */
       
  3868 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
       
  3869 
       
  3870 /*
       
  3871 ** CAPI3REF: User Data For Functions
       
  3872 **
       
  3873 ** ^The sqlite3_user_data() interface returns a copy of
       
  3874 ** the pointer that was the pUserData parameter (the 5th parameter)
       
  3875 ** of the [sqlite3_create_function()]
       
  3876 ** and [sqlite3_create_function16()] routines that originally
       
  3877 ** registered the application defined function.
       
  3878 **
       
  3879 ** This routine must be called from the same thread in which
       
  3880 ** the application-defined function is running.
       
  3881 */
       
  3882 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
       
  3883 
       
  3884 /*
       
  3885 ** CAPI3REF: Database Connection For Functions
       
  3886 **
       
  3887 ** ^The sqlite3_context_db_handle() interface returns a copy of
       
  3888 ** the pointer to the [database connection] (the 1st parameter)
       
  3889 ** of the [sqlite3_create_function()]
       
  3890 ** and [sqlite3_create_function16()] routines that originally
       
  3891 ** registered the application defined function.
       
  3892 */
       
  3893 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
       
  3894 
       
  3895 /*
       
  3896 ** CAPI3REF: Function Auxiliary Data
       
  3897 **
       
  3898 ** The following two functions may be used by scalar SQL functions to
       
  3899 ** associate metadata with argument values. If the same value is passed to
       
  3900 ** multiple invocations of the same SQL function during query execution, under
       
  3901 ** some circumstances the associated metadata may be preserved. This may
       
  3902 ** be used, for example, to add a regular-expression matching scalar
       
  3903 ** function. The compiled version of the regular expression is stored as
       
  3904 ** metadata associated with the SQL value passed as the regular expression
       
  3905 ** pattern.  The compiled regular expression can be reused on multiple
       
  3906 ** invocations of the same function so that the original pattern string
       
  3907 ** does not need to be recompiled on each invocation.
       
  3908 **
       
  3909 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
       
  3910 ** associated by the sqlite3_set_auxdata() function with the Nth argument
       
  3911 ** value to the application-defined function. ^If no metadata has been ever
       
  3912 ** been set for the Nth argument of the function, or if the corresponding
       
  3913 ** function parameter has changed since the meta-data was set,
       
  3914 ** then sqlite3_get_auxdata() returns a NULL pointer.
       
  3915 **
       
  3916 ** ^The sqlite3_set_auxdata() interface saves the metadata
       
  3917 ** pointed to by its 3rd parameter as the metadata for the N-th
       
  3918 ** argument of the application-defined function.  Subsequent
       
  3919 ** calls to sqlite3_get_auxdata() might return this data, if it has
       
  3920 ** not been destroyed.
       
  3921 ** ^If it is not NULL, SQLite will invoke the destructor
       
  3922 ** function given by the 4th parameter to sqlite3_set_auxdata() on
       
  3923 ** the metadata when the corresponding function parameter changes
       
  3924 ** or when the SQL statement completes, whichever comes first.
       
  3925 **
       
  3926 ** SQLite is free to call the destructor and drop metadata on any
       
  3927 ** parameter of any function at any time.  ^The only guarantee is that
       
  3928 ** the destructor will be called before the metadata is dropped.
       
  3929 **
       
  3930 ** ^(In practice, metadata is preserved between function calls for
       
  3931 ** expressions that are constant at compile time. This includes literal
       
  3932 ** values and [parameters].)^
       
  3933 **
       
  3934 ** These routines must be called from the same thread in which
       
  3935 ** the SQL function is running.
       
  3936 */
       
  3937 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
       
  3938 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
       
  3939 
       
  3940 
       
  3941 /*
       
  3942 ** CAPI3REF: Constants Defining Special Destructor Behavior
       
  3943 **
       
  3944 ** These are special values for the destructor that is passed in as the
       
  3945 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
       
  3946 ** argument is SQLITE_STATIC, it means that the content pointer is constant
       
  3947 ** and will never change.  It does not need to be destroyed.  ^The
       
  3948 ** SQLITE_TRANSIENT value means that the content will likely change in
       
  3949 ** the near future and that SQLite should make its own private copy of
       
  3950 ** the content before returning.
       
  3951 **
       
  3952 ** The typedef is necessary to work around problems in certain
       
  3953 ** C++ compilers.  See ticket #2191.
       
  3954 */
       
  3955 typedef void (*sqlite3_destructor_type)(void*);
       
  3956 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
       
  3957 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
       
  3958 
       
  3959 /*
       
  3960 ** CAPI3REF: Setting The Result Of An SQL Function
       
  3961 **
       
  3962 ** These routines are used by the xFunc or xFinal callbacks that
       
  3963 ** implement SQL functions and aggregates.  See
       
  3964 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
       
  3965 ** for additional information.
       
  3966 **
       
  3967 ** These functions work very much like the [parameter binding] family of
       
  3968 ** functions used to bind values to host parameters in prepared statements.
       
  3969 ** Refer to the [SQL parameter] documentation for additional information.
       
  3970 **
       
  3971 ** ^The sqlite3_result_blob() interface sets the result from
       
  3972 ** an application-defined function to be the BLOB whose content is pointed
       
  3973 ** to by the second parameter and which is N bytes long where N is the
       
  3974 ** third parameter.
       
  3975 **
       
  3976 ** ^The sqlite3_result_zeroblob() interfaces set the result of
       
  3977 ** the application-defined function to be a BLOB containing all zero
       
  3978 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
       
  3979 **
       
  3980 ** ^The sqlite3_result_double() interface sets the result from
       
  3981 ** an application-defined function to be a floating point value specified
       
  3982 ** by its 2nd argument.
       
  3983 **
       
  3984 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
       
  3985 ** cause the implemented SQL function to throw an exception.
       
  3986 ** ^SQLite uses the string pointed to by the
       
  3987 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
       
  3988 ** as the text of an error message.  ^SQLite interprets the error
       
  3989 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
       
  3990 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
       
  3991 ** byte order.  ^If the third parameter to sqlite3_result_error()
       
  3992 ** or sqlite3_result_error16() is negative then SQLite takes as the error
       
  3993 ** message all text up through the first zero character.
       
  3994 ** ^If the third parameter to sqlite3_result_error() or
       
  3995 ** sqlite3_result_error16() is non-negative then SQLite takes that many
       
  3996 ** bytes (not characters) from the 2nd parameter as the error message.
       
  3997 ** ^The sqlite3_result_error() and sqlite3_result_error16()
       
  3998 ** routines make a private copy of the error message text before
       
  3999 ** they return.  Hence, the calling function can deallocate or
       
  4000 ** modify the text after they return without harm.
       
  4001 ** ^The sqlite3_result_error_code() function changes the error code
       
  4002 ** returned by SQLite as a result of an error in a function.  ^By default,
       
  4003 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
       
  4004 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
       
  4005 **
       
  4006 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
       
  4007 ** indicating that a string or BLOB is too long to represent.
       
  4008 **
       
  4009 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
       
  4010 ** indicating that a memory allocation failed.
       
  4011 **
       
  4012 ** ^The sqlite3_result_int() interface sets the return value
       
  4013 ** of the application-defined function to be the 32-bit signed integer
       
  4014 ** value given in the 2nd argument.
       
  4015 ** ^The sqlite3_result_int64() interface sets the return value
       
  4016 ** of the application-defined function to be the 64-bit signed integer
       
  4017 ** value given in the 2nd argument.
       
  4018 **
       
  4019 ** ^The sqlite3_result_null() interface sets the return value
       
  4020 ** of the application-defined function to be NULL.
       
  4021 **
       
  4022 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
       
  4023 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
       
  4024 ** set the return value of the application-defined function to be
       
  4025 ** a text string which is represented as UTF-8, UTF-16 native byte order,
       
  4026 ** UTF-16 little endian, or UTF-16 big endian, respectively.
       
  4027 ** ^SQLite takes the text result from the application from
       
  4028 ** the 2nd parameter of the sqlite3_result_text* interfaces.
       
  4029 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
       
  4030 ** is negative, then SQLite takes result text from the 2nd parameter
       
  4031 ** through the first zero character.
       
  4032 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
       
  4033 ** is non-negative, then as many bytes (not characters) of the text
       
  4034 ** pointed to by the 2nd parameter are taken as the application-defined
       
  4035 ** function result.
       
  4036 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
       
  4037 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
       
  4038 ** function as the destructor on the text or BLOB result when it has
       
  4039 ** finished using that result.
       
  4040 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
       
  4041 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
       
  4042 ** assumes that the text or BLOB result is in constant space and does not
       
  4043 ** copy the content of the parameter nor call a destructor on the content
       
  4044 ** when it has finished using that result.
       
  4045 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
       
  4046 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
       
  4047 ** then SQLite makes a copy of the result into space obtained from
       
  4048 ** from [sqlite3_malloc()] before it returns.
       
  4049 **
       
  4050 ** ^The sqlite3_result_value() interface sets the result of
       
  4051 ** the application-defined function to be a copy the
       
  4052 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
       
  4053 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
       
  4054 ** so that the [sqlite3_value] specified in the parameter may change or
       
  4055 ** be deallocated after sqlite3_result_value() returns without harm.
       
  4056 ** ^A [protected sqlite3_value] object may always be used where an
       
  4057 ** [unprotected sqlite3_value] object is required, so either
       
  4058 ** kind of [sqlite3_value] object can be used with this interface.
       
  4059 **
       
  4060 ** If these routines are called from within the different thread
       
  4061 ** than the one containing the application-defined function that received
       
  4062 ** the [sqlite3_context] pointer, the results are undefined.
       
  4063 */
       
  4064 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
       
  4065 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
       
  4066 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
       
  4067 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
       
  4068 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
       
  4069 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
       
  4070 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
       
  4071 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
       
  4072 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
       
  4073 SQLITE_API void sqlite3_result_null(sqlite3_context*);
       
  4074 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
       
  4075 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
       
  4076 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
       
  4077 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
       
  4078 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
       
  4079 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
       
  4080 
       
  4081 /*
       
  4082 ** CAPI3REF: Define New Collating Sequences
       
  4083 **
       
  4084 ** ^These functions add, remove, or modify a [collation] associated
       
  4085 ** with the [database connection] specified as the first argument.
       
  4086 **
       
  4087 ** ^The name of the collation is a UTF-8 string
       
  4088 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
       
  4089 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
       
  4090 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
       
  4091 ** considered to be the same name.
       
  4092 **
       
  4093 ** ^(The third argument (eTextRep) must be one of the constants:
       
  4094 ** <ul>
       
  4095 ** <li> [SQLITE_UTF8],
       
  4096 ** <li> [SQLITE_UTF16LE],
       
  4097 ** <li> [SQLITE_UTF16BE],
       
  4098 ** <li> [SQLITE_UTF16], or
       
  4099 ** <li> [SQLITE_UTF16_ALIGNED].
       
  4100 ** </ul>)^
       
  4101 ** ^The eTextRep argument determines the encoding of strings passed
       
  4102 ** to the collating function callback, xCallback.
       
  4103 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
       
  4104 ** force strings to be UTF16 with native byte order.
       
  4105 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
       
  4106 ** on an even byte address.
       
  4107 **
       
  4108 ** ^The fourth argument, pArg, is an application data pointer that is passed
       
  4109 ** through as the first argument to the collating function callback.
       
  4110 **
       
  4111 ** ^The fifth argument, xCallback, is a pointer to the collating function.
       
  4112 ** ^Multiple collating functions can be registered using the same name but
       
  4113 ** with different eTextRep parameters and SQLite will use whichever
       
  4114 ** function requires the least amount of data transformation.
       
  4115 ** ^If the xCallback argument is NULL then the collating function is
       
  4116 ** deleted.  ^When all collating functions having the same name are deleted,
       
  4117 ** that collation is no longer usable.
       
  4118 **
       
  4119 ** ^The collating function callback is invoked with a copy of the pArg 
       
  4120 ** application data pointer and with two strings in the encoding specified
       
  4121 ** by the eTextRep argument.  The collating function must return an
       
  4122 ** integer that is negative, zero, or positive
       
  4123 ** if the first string is less than, equal to, or greater than the second,
       
  4124 ** respectively.  A collating function must always return the same answer
       
  4125 ** given the same inputs.  If two or more collating functions are registered
       
  4126 ** to the same collation name (using different eTextRep values) then all
       
  4127 ** must give an equivalent answer when invoked with equivalent strings.
       
  4128 ** The collating function must obey the following properties for all
       
  4129 ** strings A, B, and C:
       
  4130 **
       
  4131 ** <ol>
       
  4132 ** <li> If A==B then B==A.
       
  4133 ** <li> If A==B and B==C then A==C.
       
  4134 ** <li> If A&lt;B THEN B&gt;A.
       
  4135 ** <li> If A&lt;B and B&lt;C then A&lt;C.
       
  4136 ** </ol>
       
  4137 **
       
  4138 ** If a collating function fails any of the above constraints and that
       
  4139 ** collating function is  registered and used, then the behavior of SQLite
       
  4140 ** is undefined.
       
  4141 **
       
  4142 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
       
  4143 ** with the addition that the xDestroy callback is invoked on pArg when
       
  4144 ** the collating function is deleted.
       
  4145 ** ^Collating functions are deleted when they are overridden by later
       
  4146 ** calls to the collation creation functions or when the
       
  4147 ** [database connection] is closed using [sqlite3_close()].
       
  4148 **
       
  4149 ** ^The xDestroy callback is <u>not</u> called if the 
       
  4150 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
       
  4151 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 
       
  4152 ** check the return code and dispose of the application data pointer
       
  4153 ** themselves rather than expecting SQLite to deal with it for them.
       
  4154 ** This is different from every other SQLite interface.  The inconsistency 
       
  4155 ** is unfortunate but cannot be changed without breaking backwards 
       
  4156 ** compatibility.
       
  4157 **
       
  4158 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
       
  4159 */
       
  4160 SQLITE_API int sqlite3_create_collation(
       
  4161   sqlite3*, 
       
  4162   const char *zName, 
       
  4163   int eTextRep, 
       
  4164   void *pArg,
       
  4165   int(*xCompare)(void*,int,const void*,int,const void*)
       
  4166 );
       
  4167 SQLITE_API int sqlite3_create_collation_v2(
       
  4168   sqlite3*, 
       
  4169   const char *zName, 
       
  4170   int eTextRep, 
       
  4171   void *pArg,
       
  4172   int(*xCompare)(void*,int,const void*,int,const void*),
       
  4173   void(*xDestroy)(void*)
       
  4174 );
       
  4175 SQLITE_API int sqlite3_create_collation16(
       
  4176   sqlite3*, 
       
  4177   const void *zName,
       
  4178   int eTextRep, 
       
  4179   void *pArg,
       
  4180   int(*xCompare)(void*,int,const void*,int,const void*)
       
  4181 );
       
  4182 
       
  4183 /*
       
  4184 ** CAPI3REF: Collation Needed Callbacks
       
  4185 **
       
  4186 ** ^To avoid having to register all collation sequences before a database
       
  4187 ** can be used, a single callback function may be registered with the
       
  4188 ** [database connection] to be invoked whenever an undefined collation
       
  4189 ** sequence is required.
       
  4190 **
       
  4191 ** ^If the function is registered using the sqlite3_collation_needed() API,
       
  4192 ** then it is passed the names of undefined collation sequences as strings
       
  4193 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
       
  4194 ** the names are passed as UTF-16 in machine native byte order.
       
  4195 ** ^A call to either function replaces the existing collation-needed callback.
       
  4196 **
       
  4197 ** ^(When the callback is invoked, the first argument passed is a copy
       
  4198 ** of the second argument to sqlite3_collation_needed() or
       
  4199 ** sqlite3_collation_needed16().  The second argument is the database
       
  4200 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
       
  4201 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
       
  4202 ** sequence function required.  The fourth parameter is the name of the
       
  4203 ** required collation sequence.)^
       
  4204 **
       
  4205 ** The callback function should register the desired collation using
       
  4206 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
       
  4207 ** [sqlite3_create_collation_v2()].
       
  4208 */
       
  4209 SQLITE_API int sqlite3_collation_needed(
       
  4210   sqlite3*, 
       
  4211   void*, 
       
  4212   void(*)(void*,sqlite3*,int eTextRep,const char*)
       
  4213 );
       
  4214 SQLITE_API int sqlite3_collation_needed16(
       
  4215   sqlite3*, 
       
  4216   void*,
       
  4217   void(*)(void*,sqlite3*,int eTextRep,const void*)
       
  4218 );
       
  4219 
       
  4220 #ifdef SQLITE_HAS_CODEC
       
  4221 /*
       
  4222 ** Specify the key for an encrypted database.  This routine should be
       
  4223 ** called right after sqlite3_open().
       
  4224 **
       
  4225 ** The code to implement this API is not available in the public release
       
  4226 ** of SQLite.
       
  4227 */
       
  4228 SQLITE_API int sqlite3_key(
       
  4229   sqlite3 *db,                   /* Database to be rekeyed */
       
  4230   const void *pKey, int nKey     /* The key */
       
  4231 );
       
  4232 
       
  4233 /*
       
  4234 ** Change the key on an open database.  If the current database is not
       
  4235 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
       
  4236 ** database is decrypted.
       
  4237 **
       
  4238 ** The code to implement this API is not available in the public release
       
  4239 ** of SQLite.
       
  4240 */
       
  4241 SQLITE_API int sqlite3_rekey(
       
  4242   sqlite3 *db,                   /* Database to be rekeyed */
       
  4243   const void *pKey, int nKey     /* The new key */
       
  4244 );
       
  4245 
       
  4246 /*
       
  4247 ** Specify the activation key for a SEE database.  Unless 
       
  4248 ** activated, none of the SEE routines will work.
       
  4249 */
       
  4250 SQLITE_API void sqlite3_activate_see(
       
  4251   const char *zPassPhrase        /* Activation phrase */
       
  4252 );
       
  4253 #endif
       
  4254 
       
  4255 #ifdef SQLITE_ENABLE_CEROD
       
  4256 /*
       
  4257 ** Specify the activation key for a CEROD database.  Unless 
       
  4258 ** activated, none of the CEROD routines will work.
       
  4259 */
       
  4260 SQLITE_API void sqlite3_activate_cerod(
       
  4261   const char *zPassPhrase        /* Activation phrase */
       
  4262 );
       
  4263 #endif
       
  4264 
       
  4265 /*
       
  4266 ** CAPI3REF: Suspend Execution For A Short Time
       
  4267 **
       
  4268 ** The sqlite3_sleep() function causes the current thread to suspend execution
       
  4269 ** for at least a number of milliseconds specified in its parameter.
       
  4270 **
       
  4271 ** If the operating system does not support sleep requests with
       
  4272 ** millisecond time resolution, then the time will be rounded up to
       
  4273 ** the nearest second. The number of milliseconds of sleep actually
       
  4274 ** requested from the operating system is returned.
       
  4275 **
       
  4276 ** ^SQLite implements this interface by calling the xSleep()
       
  4277 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
       
  4278 ** of the default VFS is not implemented correctly, or not implemented at
       
  4279 ** all, then the behavior of sqlite3_sleep() may deviate from the description
       
  4280 ** in the previous paragraphs.
       
  4281 */
       
  4282 SQLITE_API int sqlite3_sleep(int);
       
  4283 
       
  4284 /*
       
  4285 ** CAPI3REF: Name Of The Folder Holding Temporary Files
       
  4286 **
       
  4287 ** ^(If this global variable is made to point to a string which is
       
  4288 ** the name of a folder (a.k.a. directory), then all temporary files
       
  4289 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
       
  4290 ** will be placed in that directory.)^  ^If this variable
       
  4291 ** is a NULL pointer, then SQLite performs a search for an appropriate
       
  4292 ** temporary file directory.
       
  4293 **
       
  4294 ** It is not safe to read or modify this variable in more than one
       
  4295 ** thread at a time.  It is not safe to read or modify this variable
       
  4296 ** if a [database connection] is being used at the same time in a separate
       
  4297 ** thread.
       
  4298 ** It is intended that this variable be set once
       
  4299 ** as part of process initialization and before any SQLite interface
       
  4300 ** routines have been called and that this variable remain unchanged
       
  4301 ** thereafter.
       
  4302 **
       
  4303 ** ^The [temp_store_directory pragma] may modify this variable and cause
       
  4304 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
       
  4305 ** the [temp_store_directory pragma] always assumes that any string
       
  4306 ** that this variable points to is held in memory obtained from 
       
  4307 ** [sqlite3_malloc] and the pragma may attempt to free that memory
       
  4308 ** using [sqlite3_free].
       
  4309 ** Hence, if this variable is modified directly, either it should be
       
  4310 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
       
  4311 ** or else the use of the [temp_store_directory pragma] should be avoided.
       
  4312 */
       
  4313 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
       
  4314 
       
  4315 /*
       
  4316 ** CAPI3REF: Test For Auto-Commit Mode
       
  4317 ** KEYWORDS: {autocommit mode}
       
  4318 **
       
  4319 ** ^The sqlite3_get_autocommit() interface returns non-zero or
       
  4320 ** zero if the given database connection is or is not in autocommit mode,
       
  4321 ** respectively.  ^Autocommit mode is on by default.
       
  4322 ** ^Autocommit mode is disabled by a [BEGIN] statement.
       
  4323 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
       
  4324 **
       
  4325 ** If certain kinds of errors occur on a statement within a multi-statement
       
  4326 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
       
  4327 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
       
  4328 ** transaction might be rolled back automatically.  The only way to
       
  4329 ** find out whether SQLite automatically rolled back the transaction after
       
  4330 ** an error is to use this function.
       
  4331 **
       
  4332 ** If another thread changes the autocommit status of the database
       
  4333 ** connection while this routine is running, then the return value
       
  4334 ** is undefined.
       
  4335 */
       
  4336 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
       
  4337 
       
  4338 /*
       
  4339 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
       
  4340 **
       
  4341 ** ^The sqlite3_db_handle interface returns the [database connection] handle
       
  4342 ** to which a [prepared statement] belongs.  ^The [database connection]
       
  4343 ** returned by sqlite3_db_handle is the same [database connection]
       
  4344 ** that was the first argument
       
  4345 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
       
  4346 ** create the statement in the first place.
       
  4347 */
       
  4348 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
       
  4349 
       
  4350 /*
       
  4351 ** CAPI3REF: Find the next prepared statement
       
  4352 **
       
  4353 ** ^This interface returns a pointer to the next [prepared statement] after
       
  4354 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
       
  4355 ** then this interface returns a pointer to the first prepared statement
       
  4356 ** associated with the database connection pDb.  ^If no prepared statement
       
  4357 ** satisfies the conditions of this routine, it returns NULL.
       
  4358 **
       
  4359 ** The [database connection] pointer D in a call to
       
  4360 ** [sqlite3_next_stmt(D,S)] must refer to an open database
       
  4361 ** connection and in particular must not be a NULL pointer.
       
  4362 */
       
  4363 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
       
  4364 
       
  4365 /*
       
  4366 ** CAPI3REF: Commit And Rollback Notification Callbacks
       
  4367 **
       
  4368 ** ^The sqlite3_commit_hook() interface registers a callback
       
  4369 ** function to be invoked whenever a transaction is [COMMIT | committed].
       
  4370 ** ^Any callback set by a previous call to sqlite3_commit_hook()
       
  4371 ** for the same database connection is overridden.
       
  4372 ** ^The sqlite3_rollback_hook() interface registers a callback
       
  4373 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
       
  4374 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
       
  4375 ** for the same database connection is overridden.
       
  4376 ** ^The pArg argument is passed through to the callback.
       
  4377 ** ^If the callback on a commit hook function returns non-zero,
       
  4378 ** then the commit is converted into a rollback.
       
  4379 **
       
  4380 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
       
  4381 ** return the P argument from the previous call of the same function
       
  4382 ** on the same [database connection] D, or NULL for
       
  4383 ** the first call for each function on D.
       
  4384 **
       
  4385 ** The callback implementation must not do anything that will modify
       
  4386 ** the database connection that invoked the callback.  Any actions
       
  4387 ** to modify the database connection must be deferred until after the
       
  4388 ** completion of the [sqlite3_step()] call that triggered the commit
       
  4389 ** or rollback hook in the first place.
       
  4390 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  4391 ** database connections for the meaning of "modify" in this paragraph.
       
  4392 **
       
  4393 ** ^Registering a NULL function disables the callback.
       
  4394 **
       
  4395 ** ^When the commit hook callback routine returns zero, the [COMMIT]
       
  4396 ** operation is allowed to continue normally.  ^If the commit hook
       
  4397 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
       
  4398 ** ^The rollback hook is invoked on a rollback that results from a commit
       
  4399 ** hook returning non-zero, just as it would be with any other rollback.
       
  4400 **
       
  4401 ** ^For the purposes of this API, a transaction is said to have been
       
  4402 ** rolled back if an explicit "ROLLBACK" statement is executed, or
       
  4403 ** an error or constraint causes an implicit rollback to occur.
       
  4404 ** ^The rollback callback is not invoked if a transaction is
       
  4405 ** automatically rolled back because the database connection is closed.
       
  4406 **
       
  4407 ** See also the [sqlite3_update_hook()] interface.
       
  4408 */
       
  4409 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
       
  4410 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
       
  4411 
       
  4412 /*
       
  4413 ** CAPI3REF: Data Change Notification Callbacks
       
  4414 **
       
  4415 ** ^The sqlite3_update_hook() interface registers a callback function
       
  4416 ** with the [database connection] identified by the first argument
       
  4417 ** to be invoked whenever a row is updated, inserted or deleted.
       
  4418 ** ^Any callback set by a previous call to this function
       
  4419 ** for the same database connection is overridden.
       
  4420 **
       
  4421 ** ^The second argument is a pointer to the function to invoke when a
       
  4422 ** row is updated, inserted or deleted.
       
  4423 ** ^The first argument to the callback is a copy of the third argument
       
  4424 ** to sqlite3_update_hook().
       
  4425 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
       
  4426 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
       
  4427 ** to be invoked.
       
  4428 ** ^The third and fourth arguments to the callback contain pointers to the
       
  4429 ** database and table name containing the affected row.
       
  4430 ** ^The final callback parameter is the [rowid] of the row.
       
  4431 ** ^In the case of an update, this is the [rowid] after the update takes place.
       
  4432 **
       
  4433 ** ^(The update hook is not invoked when internal system tables are
       
  4434 ** modified (i.e. sqlite_master and sqlite_sequence).)^
       
  4435 **
       
  4436 ** ^In the current implementation, the update hook
       
  4437 ** is not invoked when duplication rows are deleted because of an
       
  4438 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
       
  4439 ** invoked when rows are deleted using the [truncate optimization].
       
  4440 ** The exceptions defined in this paragraph might change in a future
       
  4441 ** release of SQLite.
       
  4442 **
       
  4443 ** The update hook implementation must not do anything that will modify
       
  4444 ** the database connection that invoked the update hook.  Any actions
       
  4445 ** to modify the database connection must be deferred until after the
       
  4446 ** completion of the [sqlite3_step()] call that triggered the update hook.
       
  4447 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  4448 ** database connections for the meaning of "modify" in this paragraph.
       
  4449 **
       
  4450 ** ^The sqlite3_update_hook(D,C,P) function
       
  4451 ** returns the P argument from the previous call
       
  4452 ** on the same [database connection] D, or NULL for
       
  4453 ** the first call on D.
       
  4454 **
       
  4455 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
       
  4456 ** interfaces.
       
  4457 */
       
  4458 SQLITE_API void *sqlite3_update_hook(
       
  4459   sqlite3*, 
       
  4460   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
       
  4461   void*
       
  4462 );
       
  4463 
       
  4464 /*
       
  4465 ** CAPI3REF: Enable Or Disable Shared Pager Cache
       
  4466 ** KEYWORDS: {shared cache}
       
  4467 **
       
  4468 ** ^(This routine enables or disables the sharing of the database cache
       
  4469 ** and schema data structures between [database connection | connections]
       
  4470 ** to the same database. Sharing is enabled if the argument is true
       
  4471 ** and disabled if the argument is false.)^
       
  4472 **
       
  4473 ** ^Cache sharing is enabled and disabled for an entire process.
       
  4474 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
       
  4475 ** sharing was enabled or disabled for each thread separately.
       
  4476 **
       
  4477 ** ^(The cache sharing mode set by this interface effects all subsequent
       
  4478 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
       
  4479 ** Existing database connections continue use the sharing mode
       
  4480 ** that was in effect at the time they were opened.)^
       
  4481 **
       
  4482 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
       
  4483 ** successfully.  An [error code] is returned otherwise.)^
       
  4484 **
       
  4485 ** ^Shared cache is disabled by default. But this might change in
       
  4486 ** future releases of SQLite.  Applications that care about shared
       
  4487 ** cache setting should set it explicitly.
       
  4488 **
       
  4489 ** See Also:  [SQLite Shared-Cache Mode]
       
  4490 */
       
  4491 SQLITE_API int sqlite3_enable_shared_cache(int);
       
  4492 
       
  4493 /*
       
  4494 ** CAPI3REF: Attempt To Free Heap Memory
       
  4495 **
       
  4496 ** ^The sqlite3_release_memory() interface attempts to free N bytes
       
  4497 ** of heap memory by deallocating non-essential memory allocations
       
  4498 ** held by the database library.   Memory used to cache database
       
  4499 ** pages to improve performance is an example of non-essential memory.
       
  4500 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
       
  4501 ** which might be more or less than the amount requested.
       
  4502 ** ^The sqlite3_release_memory() routine is a no-op returning zero
       
  4503 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
       
  4504 */
       
  4505 SQLITE_API int sqlite3_release_memory(int);
       
  4506 
       
  4507 /*
       
  4508 ** CAPI3REF: Impose A Limit On Heap Size
       
  4509 **
       
  4510 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
       
  4511 ** soft limit on the amount of heap memory that may be allocated by SQLite.
       
  4512 ** ^SQLite strives to keep heap memory utilization below the soft heap
       
  4513 ** limit by reducing the number of pages held in the page cache
       
  4514 ** as heap memory usages approaches the limit.
       
  4515 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
       
  4516 ** below the limit, it will exceed the limit rather than generate
       
  4517 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
       
  4518 ** is advisory only.
       
  4519 **
       
  4520 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
       
  4521 ** the soft heap limit prior to the call.  ^If the argument N is negative
       
  4522 ** then no change is made to the soft heap limit.  Hence, the current
       
  4523 ** size of the soft heap limit can be determined by invoking
       
  4524 ** sqlite3_soft_heap_limit64() with a negative argument.
       
  4525 **
       
  4526 ** ^If the argument N is zero then the soft heap limit is disabled.
       
  4527 **
       
  4528 ** ^(The soft heap limit is not enforced in the current implementation
       
  4529 ** if one or more of following conditions are true:
       
  4530 **
       
  4531 ** <ul>
       
  4532 ** <li> The soft heap limit is set to zero.
       
  4533 ** <li> Memory accounting is disabled using a combination of the
       
  4534 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
       
  4535 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
       
  4536 ** <li> An alternative page cache implementation is specified using
       
  4537 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
       
  4538 ** <li> The page cache allocates from its own memory pool supplied
       
  4539 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
       
  4540 **      from the heap.
       
  4541 ** </ul>)^
       
  4542 **
       
  4543 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
       
  4544 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
       
  4545 ** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
       
  4546 ** the soft heap limit is enforced on every memory allocation.  Without
       
  4547 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
       
  4548 ** when memory is allocated by the page cache.  Testing suggests that because
       
  4549 ** the page cache is the predominate memory user in SQLite, most
       
  4550 ** applications will achieve adequate soft heap limit enforcement without
       
  4551 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
       
  4552 **
       
  4553 ** The circumstances under which SQLite will enforce the soft heap limit may
       
  4554 ** changes in future releases of SQLite.
       
  4555 */
       
  4556 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
       
  4557 
       
  4558 /*
       
  4559 ** CAPI3REF: Deprecated Soft Heap Limit Interface
       
  4560 ** DEPRECATED
       
  4561 **
       
  4562 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
       
  4563 ** interface.  This routine is provided for historical compatibility
       
  4564 ** only.  All new applications should use the
       
  4565 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
       
  4566 */
       
  4567 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
       
  4568 
       
  4569 
       
  4570 /*
       
  4571 ** CAPI3REF: Extract Metadata About A Column Of A Table
       
  4572 **
       
  4573 ** ^This routine returns metadata about a specific column of a specific
       
  4574 ** database table accessible using the [database connection] handle
       
  4575 ** passed as the first function argument.
       
  4576 **
       
  4577 ** ^The column is identified by the second, third and fourth parameters to
       
  4578 ** this function. ^The second parameter is either the name of the database
       
  4579 ** (i.e. "main", "temp", or an attached database) containing the specified
       
  4580 ** table or NULL. ^If it is NULL, then all attached databases are searched
       
  4581 ** for the table using the same algorithm used by the database engine to
       
  4582 ** resolve unqualified table references.
       
  4583 **
       
  4584 ** ^The third and fourth parameters to this function are the table and column
       
  4585 ** name of the desired column, respectively. Neither of these parameters
       
  4586 ** may be NULL.
       
  4587 **
       
  4588 ** ^Metadata is returned by writing to the memory locations passed as the 5th
       
  4589 ** and subsequent parameters to this function. ^Any of these arguments may be
       
  4590 ** NULL, in which case the corresponding element of metadata is omitted.
       
  4591 **
       
  4592 ** ^(<blockquote>
       
  4593 ** <table border="1">
       
  4594 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
       
  4595 **
       
  4596 ** <tr><td> 5th <td> const char* <td> Data type
       
  4597 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
       
  4598 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
       
  4599 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
       
  4600 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
       
  4601 ** </table>
       
  4602 ** </blockquote>)^
       
  4603 **
       
  4604 ** ^The memory pointed to by the character pointers returned for the
       
  4605 ** declaration type and collation sequence is valid only until the next
       
  4606 ** call to any SQLite API function.
       
  4607 **
       
  4608 ** ^If the specified table is actually a view, an [error code] is returned.
       
  4609 **
       
  4610 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
       
  4611 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
       
  4612 ** parameters are set for the explicitly declared column. ^(If there is no
       
  4613 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
       
  4614 ** parameters are set as follows:
       
  4615 **
       
  4616 ** <pre>
       
  4617 **     data type: "INTEGER"
       
  4618 **     collation sequence: "BINARY"
       
  4619 **     not null: 0
       
  4620 **     primary key: 1
       
  4621 **     auto increment: 0
       
  4622 ** </pre>)^
       
  4623 **
       
  4624 ** ^(This function may load one or more schemas from database files. If an
       
  4625 ** error occurs during this process, or if the requested table or column
       
  4626 ** cannot be found, an [error code] is returned and an error message left
       
  4627 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
       
  4628 **
       
  4629 ** ^This API is only available if the library was compiled with the
       
  4630 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
       
  4631 */
       
  4632 SQLITE_API int sqlite3_table_column_metadata(
       
  4633   sqlite3 *db,                /* Connection handle */
       
  4634   const char *zDbName,        /* Database name or NULL */
       
  4635   const char *zTableName,     /* Table name */
       
  4636   const char *zColumnName,    /* Column name */
       
  4637   char const **pzDataType,    /* OUTPUT: Declared data type */
       
  4638   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
       
  4639   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
       
  4640   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
       
  4641   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
       
  4642 );
       
  4643 
       
  4644 /*
       
  4645 ** CAPI3REF: Load An Extension
       
  4646 **
       
  4647 ** ^This interface loads an SQLite extension library from the named file.
       
  4648 **
       
  4649 ** ^The sqlite3_load_extension() interface attempts to load an
       
  4650 ** SQLite extension library contained in the file zFile.
       
  4651 **
       
  4652 ** ^The entry point is zProc.
       
  4653 ** ^zProc may be 0, in which case the name of the entry point
       
  4654 ** defaults to "sqlite3_extension_init".
       
  4655 ** ^The sqlite3_load_extension() interface returns
       
  4656 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
       
  4657 ** ^If an error occurs and pzErrMsg is not 0, then the
       
  4658 ** [sqlite3_load_extension()] interface shall attempt to
       
  4659 ** fill *pzErrMsg with error message text stored in memory
       
  4660 ** obtained from [sqlite3_malloc()]. The calling function
       
  4661 ** should free this memory by calling [sqlite3_free()].
       
  4662 **
       
  4663 ** ^Extension loading must be enabled using
       
  4664 ** [sqlite3_enable_load_extension()] prior to calling this API,
       
  4665 ** otherwise an error will be returned.
       
  4666 **
       
  4667 ** See also the [load_extension() SQL function].
       
  4668 */
       
  4669 SQLITE_API int sqlite3_load_extension(
       
  4670   sqlite3 *db,          /* Load the extension into this database connection */
       
  4671   const char *zFile,    /* Name of the shared library containing extension */
       
  4672   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
       
  4673   char **pzErrMsg       /* Put error message here if not 0 */
       
  4674 );
       
  4675 
       
  4676 /*
       
  4677 ** CAPI3REF: Enable Or Disable Extension Loading
       
  4678 **
       
  4679 ** ^So as not to open security holes in older applications that are
       
  4680 ** unprepared to deal with extension loading, and as a means of disabling
       
  4681 ** extension loading while evaluating user-entered SQL, the following API
       
  4682 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
       
  4683 **
       
  4684 ** ^Extension loading is off by default. See ticket #1863.
       
  4685 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
       
  4686 ** to turn extension loading on and call it with onoff==0 to turn
       
  4687 ** it back off again.
       
  4688 */
       
  4689 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
       
  4690 
       
  4691 /*
       
  4692 ** CAPI3REF: Automatically Load Statically Linked Extensions
       
  4693 **
       
  4694 ** ^This interface causes the xEntryPoint() function to be invoked for
       
  4695 ** each new [database connection] that is created.  The idea here is that
       
  4696 ** xEntryPoint() is the entry point for a statically linked SQLite extension
       
  4697 ** that is to be automatically loaded into all new database connections.
       
  4698 **
       
  4699 ** ^(Even though the function prototype shows that xEntryPoint() takes
       
  4700 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
       
  4701 ** arguments and expects and integer result as if the signature of the
       
  4702 ** entry point where as follows:
       
  4703 **
       
  4704 ** <blockquote><pre>
       
  4705 ** &nbsp;  int xEntryPoint(
       
  4706 ** &nbsp;    sqlite3 *db,
       
  4707 ** &nbsp;    const char **pzErrMsg,
       
  4708 ** &nbsp;    const struct sqlite3_api_routines *pThunk
       
  4709 ** &nbsp;  );
       
  4710 ** </pre></blockquote>)^
       
  4711 **
       
  4712 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
       
  4713 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
       
  4714 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
       
  4715 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
       
  4716 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
       
  4717 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
       
  4718 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
       
  4719 **
       
  4720 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
       
  4721 ** on the list of automatic extensions is a harmless no-op. ^No entry point
       
  4722 ** will be called more than once for each database connection that is opened.
       
  4723 **
       
  4724 ** See also: [sqlite3_reset_auto_extension()].
       
  4725 */
       
  4726 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
       
  4727 
       
  4728 /*
       
  4729 ** CAPI3REF: Reset Automatic Extension Loading
       
  4730 **
       
  4731 ** ^This interface disables all automatic extensions previously
       
  4732 ** registered using [sqlite3_auto_extension()].
       
  4733 */
       
  4734 SQLITE_API void sqlite3_reset_auto_extension(void);
       
  4735 
       
  4736 /*
       
  4737 ** The interface to the virtual-table mechanism is currently considered
       
  4738 ** to be experimental.  The interface might change in incompatible ways.
       
  4739 ** If this is a problem for you, do not use the interface at this time.
       
  4740 **
       
  4741 ** When the virtual-table mechanism stabilizes, we will declare the
       
  4742 ** interface fixed, support it indefinitely, and remove this comment.
       
  4743 */
       
  4744 
       
  4745 /*
       
  4746 ** Structures used by the virtual table interface
       
  4747 */
       
  4748 typedef struct sqlite3_vtab sqlite3_vtab;
       
  4749 typedef struct sqlite3_index_info sqlite3_index_info;
       
  4750 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
       
  4751 typedef struct sqlite3_module sqlite3_module;
       
  4752 
       
  4753 /*
       
  4754 ** CAPI3REF: Virtual Table Object
       
  4755 ** KEYWORDS: sqlite3_module {virtual table module}
       
  4756 **
       
  4757 ** This structure, sometimes called a "virtual table module", 
       
  4758 ** defines the implementation of a [virtual tables].  
       
  4759 ** This structure consists mostly of methods for the module.
       
  4760 **
       
  4761 ** ^A virtual table module is created by filling in a persistent
       
  4762 ** instance of this structure and passing a pointer to that instance
       
  4763 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
       
  4764 ** ^The registration remains valid until it is replaced by a different
       
  4765 ** module or until the [database connection] closes.  The content
       
  4766 ** of this structure must not change while it is registered with
       
  4767 ** any database connection.
       
  4768 */
       
  4769 struct sqlite3_module {
       
  4770   int iVersion;
       
  4771   int (*xCreate)(sqlite3*, void *pAux,
       
  4772                int argc, const char *const*argv,
       
  4773                sqlite3_vtab **ppVTab, char**);
       
  4774   int (*xConnect)(sqlite3*, void *pAux,
       
  4775                int argc, const char *const*argv,
       
  4776                sqlite3_vtab **ppVTab, char**);
       
  4777   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
       
  4778   int (*xDisconnect)(sqlite3_vtab *pVTab);
       
  4779   int (*xDestroy)(sqlite3_vtab *pVTab);
       
  4780   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
       
  4781   int (*xClose)(sqlite3_vtab_cursor*);
       
  4782   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
       
  4783                 int argc, sqlite3_value **argv);
       
  4784   int (*xNext)(sqlite3_vtab_cursor*);
       
  4785   int (*xEof)(sqlite3_vtab_cursor*);
       
  4786   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
       
  4787   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
       
  4788   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
       
  4789   int (*xBegin)(sqlite3_vtab *pVTab);
       
  4790   int (*xSync)(sqlite3_vtab *pVTab);
       
  4791   int (*xCommit)(sqlite3_vtab *pVTab);
       
  4792   int (*xRollback)(sqlite3_vtab *pVTab);
       
  4793   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
       
  4794                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
       
  4795                        void **ppArg);
       
  4796   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
       
  4797   /* The methods above are in version 1 of the sqlite_module object. Those 
       
  4798   ** below are for version 2 and greater. */
       
  4799   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
       
  4800   int (*xRelease)(sqlite3_vtab *pVTab, int);
       
  4801   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
       
  4802 };
       
  4803 
       
  4804 /*
       
  4805 ** CAPI3REF: Virtual Table Indexing Information
       
  4806 ** KEYWORDS: sqlite3_index_info
       
  4807 **
       
  4808 ** The sqlite3_index_info structure and its substructures is used as part
       
  4809 ** of the [virtual table] interface to
       
  4810 ** pass information into and receive the reply from the [xBestIndex]
       
  4811 ** method of a [virtual table module].  The fields under **Inputs** are the
       
  4812 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
       
  4813 ** results into the **Outputs** fields.
       
  4814 **
       
  4815 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
       
  4816 **
       
  4817 ** <blockquote>column OP expr</blockquote>
       
  4818 **
       
  4819 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
       
  4820 ** stored in aConstraint[].op using one of the
       
  4821 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
       
  4822 ** ^(The index of the column is stored in
       
  4823 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
       
  4824 ** expr on the right-hand side can be evaluated (and thus the constraint
       
  4825 ** is usable) and false if it cannot.)^
       
  4826 **
       
  4827 ** ^The optimizer automatically inverts terms of the form "expr OP column"
       
  4828 ** and makes other simplifications to the WHERE clause in an attempt to
       
  4829 ** get as many WHERE clause terms into the form shown above as possible.
       
  4830 ** ^The aConstraint[] array only reports WHERE clause terms that are
       
  4831 ** relevant to the particular virtual table being queried.
       
  4832 **
       
  4833 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
       
  4834 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
       
  4835 **
       
  4836 ** The [xBestIndex] method must fill aConstraintUsage[] with information
       
  4837 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
       
  4838 ** the right-hand side of the corresponding aConstraint[] is evaluated
       
  4839 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
       
  4840 ** is true, then the constraint is assumed to be fully handled by the
       
  4841 ** virtual table and is not checked again by SQLite.)^
       
  4842 **
       
  4843 ** ^The idxNum and idxPtr values are recorded and passed into the
       
  4844 ** [xFilter] method.
       
  4845 ** ^[sqlite3_free()] is used to free idxPtr if and only if
       
  4846 ** needToFreeIdxPtr is true.
       
  4847 **
       
  4848 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
       
  4849 ** the correct order to satisfy the ORDER BY clause so that no separate
       
  4850 ** sorting step is required.
       
  4851 **
       
  4852 ** ^The estimatedCost value is an estimate of the cost of doing the
       
  4853 ** particular lookup.  A full scan of a table with N entries should have
       
  4854 ** a cost of N.  A binary search of a table of N entries should have a
       
  4855 ** cost of approximately log(N).
       
  4856 */
       
  4857 struct sqlite3_index_info {
       
  4858   /* Inputs */
       
  4859   int nConstraint;           /* Number of entries in aConstraint */
       
  4860   struct sqlite3_index_constraint {
       
  4861      int iColumn;              /* Column on left-hand side of constraint */
       
  4862      unsigned char op;         /* Constraint operator */
       
  4863      unsigned char usable;     /* True if this constraint is usable */
       
  4864      int iTermOffset;          /* Used internally - xBestIndex should ignore */
       
  4865   } *aConstraint;            /* Table of WHERE clause constraints */
       
  4866   int nOrderBy;              /* Number of terms in the ORDER BY clause */
       
  4867   struct sqlite3_index_orderby {
       
  4868      int iColumn;              /* Column number */
       
  4869      unsigned char desc;       /* True for DESC.  False for ASC. */
       
  4870   } *aOrderBy;               /* The ORDER BY clause */
       
  4871   /* Outputs */
       
  4872   struct sqlite3_index_constraint_usage {
       
  4873     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
       
  4874     unsigned char omit;      /* Do not code a test for this constraint */
       
  4875   } *aConstraintUsage;
       
  4876   int idxNum;                /* Number used to identify the index */
       
  4877   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
       
  4878   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
       
  4879   int orderByConsumed;       /* True if output is already ordered */
       
  4880   double estimatedCost;      /* Estimated cost of using this index */
       
  4881 };
       
  4882 
       
  4883 /*
       
  4884 ** CAPI3REF: Virtual Table Constraint Operator Codes
       
  4885 **
       
  4886 ** These macros defined the allowed values for the
       
  4887 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
       
  4888 ** an operator that is part of a constraint term in the wHERE clause of
       
  4889 ** a query that uses a [virtual table].
       
  4890 */
       
  4891 #define SQLITE_INDEX_CONSTRAINT_EQ    2
       
  4892 #define SQLITE_INDEX_CONSTRAINT_GT    4
       
  4893 #define SQLITE_INDEX_CONSTRAINT_LE    8
       
  4894 #define SQLITE_INDEX_CONSTRAINT_LT    16
       
  4895 #define SQLITE_INDEX_CONSTRAINT_GE    32
       
  4896 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
       
  4897 
       
  4898 /*
       
  4899 ** CAPI3REF: Register A Virtual Table Implementation
       
  4900 **
       
  4901 ** ^These routines are used to register a new [virtual table module] name.
       
  4902 ** ^Module names must be registered before
       
  4903 ** creating a new [virtual table] using the module and before using a
       
  4904 ** preexisting [virtual table] for the module.
       
  4905 **
       
  4906 ** ^The module name is registered on the [database connection] specified
       
  4907 ** by the first parameter.  ^The name of the module is given by the 
       
  4908 ** second parameter.  ^The third parameter is a pointer to
       
  4909 ** the implementation of the [virtual table module].   ^The fourth
       
  4910 ** parameter is an arbitrary client data pointer that is passed through
       
  4911 ** into the [xCreate] and [xConnect] methods of the virtual table module
       
  4912 ** when a new virtual table is be being created or reinitialized.
       
  4913 **
       
  4914 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
       
  4915 ** is a pointer to a destructor for the pClientData.  ^SQLite will
       
  4916 ** invoke the destructor function (if it is not NULL) when SQLite
       
  4917 ** no longer needs the pClientData pointer.  ^The destructor will also
       
  4918 ** be invoked if the call to sqlite3_create_module_v2() fails.
       
  4919 ** ^The sqlite3_create_module()
       
  4920 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
       
  4921 ** destructor.
       
  4922 */
       
  4923 SQLITE_API int sqlite3_create_module(
       
  4924   sqlite3 *db,               /* SQLite connection to register module with */
       
  4925   const char *zName,         /* Name of the module */
       
  4926   const sqlite3_module *p,   /* Methods for the module */
       
  4927   void *pClientData          /* Client data for xCreate/xConnect */
       
  4928 );
       
  4929 SQLITE_API int sqlite3_create_module_v2(
       
  4930   sqlite3 *db,               /* SQLite connection to register module with */
       
  4931   const char *zName,         /* Name of the module */
       
  4932   const sqlite3_module *p,   /* Methods for the module */
       
  4933   void *pClientData,         /* Client data for xCreate/xConnect */
       
  4934   void(*xDestroy)(void*)     /* Module destructor function */
       
  4935 );
       
  4936 
       
  4937 /*
       
  4938 ** CAPI3REF: Virtual Table Instance Object
       
  4939 ** KEYWORDS: sqlite3_vtab
       
  4940 **
       
  4941 ** Every [virtual table module] implementation uses a subclass
       
  4942 ** of this object to describe a particular instance
       
  4943 ** of the [virtual table].  Each subclass will
       
  4944 ** be tailored to the specific needs of the module implementation.
       
  4945 ** The purpose of this superclass is to define certain fields that are
       
  4946 ** common to all module implementations.
       
  4947 **
       
  4948 ** ^Virtual tables methods can set an error message by assigning a
       
  4949 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
       
  4950 ** take care that any prior string is freed by a call to [sqlite3_free()]
       
  4951 ** prior to assigning a new string to zErrMsg.  ^After the error message
       
  4952 ** is delivered up to the client application, the string will be automatically
       
  4953 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
       
  4954 */
       
  4955 struct sqlite3_vtab {
       
  4956   const sqlite3_module *pModule;  /* The module for this virtual table */
       
  4957   int nRef;                       /* NO LONGER USED */
       
  4958   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
       
  4959   /* Virtual table implementations will typically add additional fields */
       
  4960 };
       
  4961 
       
  4962 /*
       
  4963 ** CAPI3REF: Virtual Table Cursor Object
       
  4964 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
       
  4965 **
       
  4966 ** Every [virtual table module] implementation uses a subclass of the
       
  4967 ** following structure to describe cursors that point into the
       
  4968 ** [virtual table] and are used
       
  4969 ** to loop through the virtual table.  Cursors are created using the
       
  4970 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
       
  4971 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
       
  4972 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
       
  4973 ** of the module.  Each module implementation will define
       
  4974 ** the content of a cursor structure to suit its own needs.
       
  4975 **
       
  4976 ** This superclass exists in order to define fields of the cursor that
       
  4977 ** are common to all implementations.
       
  4978 */
       
  4979 struct sqlite3_vtab_cursor {
       
  4980   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
       
  4981   /* Virtual table implementations will typically add additional fields */
       
  4982 };
       
  4983 
       
  4984 /*
       
  4985 ** CAPI3REF: Declare The Schema Of A Virtual Table
       
  4986 **
       
  4987 ** ^The [xCreate] and [xConnect] methods of a
       
  4988 ** [virtual table module] call this interface
       
  4989 ** to declare the format (the names and datatypes of the columns) of
       
  4990 ** the virtual tables they implement.
       
  4991 */
       
  4992 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
       
  4993 
       
  4994 /*
       
  4995 ** CAPI3REF: Overload A Function For A Virtual Table
       
  4996 **
       
  4997 ** ^(Virtual tables can provide alternative implementations of functions
       
  4998 ** using the [xFindFunction] method of the [virtual table module].  
       
  4999 ** But global versions of those functions
       
  5000 ** must exist in order to be overloaded.)^
       
  5001 **
       
  5002 ** ^(This API makes sure a global version of a function with a particular
       
  5003 ** name and number of parameters exists.  If no such function exists
       
  5004 ** before this API is called, a new function is created.)^  ^The implementation
       
  5005 ** of the new function always causes an exception to be thrown.  So
       
  5006 ** the new function is not good for anything by itself.  Its only
       
  5007 ** purpose is to be a placeholder function that can be overloaded
       
  5008 ** by a [virtual table].
       
  5009 */
       
  5010 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
       
  5011 
       
  5012 /*
       
  5013 ** The interface to the virtual-table mechanism defined above (back up
       
  5014 ** to a comment remarkably similar to this one) is currently considered
       
  5015 ** to be experimental.  The interface might change in incompatible ways.
       
  5016 ** If this is a problem for you, do not use the interface at this time.
       
  5017 **
       
  5018 ** When the virtual-table mechanism stabilizes, we will declare the
       
  5019 ** interface fixed, support it indefinitely, and remove this comment.
       
  5020 */
       
  5021 
       
  5022 /*
       
  5023 ** CAPI3REF: A Handle To An Open BLOB
       
  5024 ** KEYWORDS: {BLOB handle} {BLOB handles}
       
  5025 **
       
  5026 ** An instance of this object represents an open BLOB on which
       
  5027 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
       
  5028 ** ^Objects of this type are created by [sqlite3_blob_open()]
       
  5029 ** and destroyed by [sqlite3_blob_close()].
       
  5030 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
       
  5031 ** can be used to read or write small subsections of the BLOB.
       
  5032 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
       
  5033 */
       
  5034 typedef struct sqlite3_blob sqlite3_blob;
       
  5035 
       
  5036 /*
       
  5037 ** CAPI3REF: Open A BLOB For Incremental I/O
       
  5038 **
       
  5039 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
       
  5040 ** in row iRow, column zColumn, table zTable in database zDb;
       
  5041 ** in other words, the same BLOB that would be selected by:
       
  5042 **
       
  5043 ** <pre>
       
  5044 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
       
  5045 ** </pre>)^
       
  5046 **
       
  5047 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
       
  5048 ** and write access. ^If it is zero, the BLOB is opened for read access.
       
  5049 ** ^It is not possible to open a column that is part of an index or primary 
       
  5050 ** key for writing. ^If [foreign key constraints] are enabled, it is 
       
  5051 ** not possible to open a column that is part of a [child key] for writing.
       
  5052 **
       
  5053 ** ^Note that the database name is not the filename that contains
       
  5054 ** the database but rather the symbolic name of the database that
       
  5055 ** appears after the AS keyword when the database is connected using [ATTACH].
       
  5056 ** ^For the main database file, the database name is "main".
       
  5057 ** ^For TEMP tables, the database name is "temp".
       
  5058 **
       
  5059 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
       
  5060 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
       
  5061 ** to be a null pointer.)^
       
  5062 ** ^This function sets the [database connection] error code and message
       
  5063 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
       
  5064 ** functions. ^Note that the *ppBlob variable is always initialized in a
       
  5065 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
       
  5066 ** regardless of the success or failure of this routine.
       
  5067 **
       
  5068 ** ^(If the row that a BLOB handle points to is modified by an
       
  5069 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
       
  5070 ** then the BLOB handle is marked as "expired".
       
  5071 ** This is true if any column of the row is changed, even a column
       
  5072 ** other than the one the BLOB handle is open on.)^
       
  5073 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
       
  5074 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
       
  5075 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
       
  5076 ** rolled back by the expiration of the BLOB.  Such changes will eventually
       
  5077 ** commit if the transaction continues to completion.)^
       
  5078 **
       
  5079 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
       
  5080 ** the opened blob.  ^The size of a blob may not be changed by this
       
  5081 ** interface.  Use the [UPDATE] SQL command to change the size of a
       
  5082 ** blob.
       
  5083 **
       
  5084 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
       
  5085 ** and the built-in [zeroblob] SQL function can be used, if desired,
       
  5086 ** to create an empty, zero-filled blob in which to read or write using
       
  5087 ** this interface.
       
  5088 **
       
  5089 ** To avoid a resource leak, every open [BLOB handle] should eventually
       
  5090 ** be released by a call to [sqlite3_blob_close()].
       
  5091 */
       
  5092 SQLITE_API int sqlite3_blob_open(
       
  5093   sqlite3*,
       
  5094   const char *zDb,
       
  5095   const char *zTable,
       
  5096   const char *zColumn,
       
  5097   sqlite3_int64 iRow,
       
  5098   int flags,
       
  5099   sqlite3_blob **ppBlob
       
  5100 );
       
  5101 
       
  5102 /*
       
  5103 ** CAPI3REF: Move a BLOB Handle to a New Row
       
  5104 **
       
  5105 ** ^This function is used to move an existing blob handle so that it points
       
  5106 ** to a different row of the same database table. ^The new row is identified
       
  5107 ** by the rowid value passed as the second argument. Only the row can be
       
  5108 ** changed. ^The database, table and column on which the blob handle is open
       
  5109 ** remain the same. Moving an existing blob handle to a new row can be
       
  5110 ** faster than closing the existing handle and opening a new one.
       
  5111 **
       
  5112 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
       
  5113 ** it must exist and there must be either a blob or text value stored in
       
  5114 ** the nominated column.)^ ^If the new row is not present in the table, or if
       
  5115 ** it does not contain a blob or text value, or if another error occurs, an
       
  5116 ** SQLite error code is returned and the blob handle is considered aborted.
       
  5117 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
       
  5118 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
       
  5119 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
       
  5120 ** always returns zero.
       
  5121 **
       
  5122 ** ^This function sets the database handle error code and message.
       
  5123 */
       
  5124 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
       
  5125 
       
  5126 /*
       
  5127 ** CAPI3REF: Close A BLOB Handle
       
  5128 **
       
  5129 ** ^Closes an open [BLOB handle].
       
  5130 **
       
  5131 ** ^Closing a BLOB shall cause the current transaction to commit
       
  5132 ** if there are no other BLOBs, no pending prepared statements, and the
       
  5133 ** database connection is in [autocommit mode].
       
  5134 ** ^If any writes were made to the BLOB, they might be held in cache
       
  5135 ** until the close operation if they will fit.
       
  5136 **
       
  5137 ** ^(Closing the BLOB often forces the changes
       
  5138 ** out to disk and so if any I/O errors occur, they will likely occur
       
  5139 ** at the time when the BLOB is closed.  Any errors that occur during
       
  5140 ** closing are reported as a non-zero return value.)^
       
  5141 **
       
  5142 ** ^(The BLOB is closed unconditionally.  Even if this routine returns
       
  5143 ** an error code, the BLOB is still closed.)^
       
  5144 **
       
  5145 ** ^Calling this routine with a null pointer (such as would be returned
       
  5146 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
       
  5147 */
       
  5148 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
       
  5149 
       
  5150 /*
       
  5151 ** CAPI3REF: Return The Size Of An Open BLOB
       
  5152 **
       
  5153 ** ^Returns the size in bytes of the BLOB accessible via the 
       
  5154 ** successfully opened [BLOB handle] in its only argument.  ^The
       
  5155 ** incremental blob I/O routines can only read or overwriting existing
       
  5156 ** blob content; they cannot change the size of a blob.
       
  5157 **
       
  5158 ** This routine only works on a [BLOB handle] which has been created
       
  5159 ** by a prior successful call to [sqlite3_blob_open()] and which has not
       
  5160 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
       
  5161 ** to this routine results in undefined and probably undesirable behavior.
       
  5162 */
       
  5163 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
       
  5164 
       
  5165 /*
       
  5166 ** CAPI3REF: Read Data From A BLOB Incrementally
       
  5167 **
       
  5168 ** ^(This function is used to read data from an open [BLOB handle] into a
       
  5169 ** caller-supplied buffer. N bytes of data are copied into buffer Z
       
  5170 ** from the open BLOB, starting at offset iOffset.)^
       
  5171 **
       
  5172 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
       
  5173 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
       
  5174 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
       
  5175 ** ^The size of the blob (and hence the maximum value of N+iOffset)
       
  5176 ** can be determined using the [sqlite3_blob_bytes()] interface.
       
  5177 **
       
  5178 ** ^An attempt to read from an expired [BLOB handle] fails with an
       
  5179 ** error code of [SQLITE_ABORT].
       
  5180 **
       
  5181 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
       
  5182 ** Otherwise, an [error code] or an [extended error code] is returned.)^
       
  5183 **
       
  5184 ** This routine only works on a [BLOB handle] which has been created
       
  5185 ** by a prior successful call to [sqlite3_blob_open()] and which has not
       
  5186 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
       
  5187 ** to this routine results in undefined and probably undesirable behavior.
       
  5188 **
       
  5189 ** See also: [sqlite3_blob_write()].
       
  5190 */
       
  5191 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
       
  5192 
       
  5193 /*
       
  5194 ** CAPI3REF: Write Data Into A BLOB Incrementally
       
  5195 **
       
  5196 ** ^This function is used to write data into an open [BLOB handle] from a
       
  5197 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
       
  5198 ** into the open BLOB, starting at offset iOffset.
       
  5199 **
       
  5200 ** ^If the [BLOB handle] passed as the first argument was not opened for
       
  5201 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
       
  5202 ** this function returns [SQLITE_READONLY].
       
  5203 **
       
  5204 ** ^This function may only modify the contents of the BLOB; it is
       
  5205 ** not possible to increase the size of a BLOB using this API.
       
  5206 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
       
  5207 ** [SQLITE_ERROR] is returned and no data is written.  ^If N is
       
  5208 ** less than zero [SQLITE_ERROR] is returned and no data is written.
       
  5209 ** The size of the BLOB (and hence the maximum value of N+iOffset)
       
  5210 ** can be determined using the [sqlite3_blob_bytes()] interface.
       
  5211 **
       
  5212 ** ^An attempt to write to an expired [BLOB handle] fails with an
       
  5213 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
       
  5214 ** before the [BLOB handle] expired are not rolled back by the
       
  5215 ** expiration of the handle, though of course those changes might
       
  5216 ** have been overwritten by the statement that expired the BLOB handle
       
  5217 ** or by other independent statements.
       
  5218 **
       
  5219 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
       
  5220 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
       
  5221 **
       
  5222 ** This routine only works on a [BLOB handle] which has been created
       
  5223 ** by a prior successful call to [sqlite3_blob_open()] and which has not
       
  5224 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
       
  5225 ** to this routine results in undefined and probably undesirable behavior.
       
  5226 **
       
  5227 ** See also: [sqlite3_blob_read()].
       
  5228 */
       
  5229 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
       
  5230 
       
  5231 /*
       
  5232 ** CAPI3REF: Virtual File System Objects
       
  5233 **
       
  5234 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
       
  5235 ** that SQLite uses to interact
       
  5236 ** with the underlying operating system.  Most SQLite builds come with a
       
  5237 ** single default VFS that is appropriate for the host computer.
       
  5238 ** New VFSes can be registered and existing VFSes can be unregistered.
       
  5239 ** The following interfaces are provided.
       
  5240 **
       
  5241 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
       
  5242 ** ^Names are case sensitive.
       
  5243 ** ^Names are zero-terminated UTF-8 strings.
       
  5244 ** ^If there is no match, a NULL pointer is returned.
       
  5245 ** ^If zVfsName is NULL then the default VFS is returned.
       
  5246 **
       
  5247 ** ^New VFSes are registered with sqlite3_vfs_register().
       
  5248 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
       
  5249 ** ^The same VFS can be registered multiple times without injury.
       
  5250 ** ^To make an existing VFS into the default VFS, register it again
       
  5251 ** with the makeDflt flag set.  If two different VFSes with the
       
  5252 ** same name are registered, the behavior is undefined.  If a
       
  5253 ** VFS is registered with a name that is NULL or an empty string,
       
  5254 ** then the behavior is undefined.
       
  5255 **
       
  5256 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
       
  5257 ** ^(If the default VFS is unregistered, another VFS is chosen as
       
  5258 ** the default.  The choice for the new VFS is arbitrary.)^
       
  5259 */
       
  5260 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
       
  5261 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
       
  5262 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
       
  5263 
       
  5264 /*
       
  5265 ** CAPI3REF: Mutexes
       
  5266 **
       
  5267 ** The SQLite core uses these routines for thread
       
  5268 ** synchronization. Though they are intended for internal
       
  5269 ** use by SQLite, code that links against SQLite is
       
  5270 ** permitted to use any of these routines.
       
  5271 **
       
  5272 ** The SQLite source code contains multiple implementations
       
  5273 ** of these mutex routines.  An appropriate implementation
       
  5274 ** is selected automatically at compile-time.  ^(The following
       
  5275 ** implementations are available in the SQLite core:
       
  5276 **
       
  5277 ** <ul>
       
  5278 ** <li>   SQLITE_MUTEX_OS2
       
  5279 ** <li>   SQLITE_MUTEX_PTHREAD
       
  5280 ** <li>   SQLITE_MUTEX_W32
       
  5281 ** <li>   SQLITE_MUTEX_NOOP
       
  5282 ** </ul>)^
       
  5283 **
       
  5284 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
       
  5285 ** that does no real locking and is appropriate for use in
       
  5286 ** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
       
  5287 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
       
  5288 ** are appropriate for use on OS/2, Unix, and Windows.
       
  5289 **
       
  5290 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
       
  5291 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
       
  5292 ** implementation is included with the library. In this case the
       
  5293 ** application must supply a custom mutex implementation using the
       
  5294 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
       
  5295 ** before calling sqlite3_initialize() or any other public sqlite3_
       
  5296 ** function that calls sqlite3_initialize().)^
       
  5297 **
       
  5298 ** ^The sqlite3_mutex_alloc() routine allocates a new
       
  5299 ** mutex and returns a pointer to it. ^If it returns NULL
       
  5300 ** that means that a mutex could not be allocated.  ^SQLite
       
  5301 ** will unwind its stack and return an error.  ^(The argument
       
  5302 ** to sqlite3_mutex_alloc() is one of these integer constants:
       
  5303 **
       
  5304 ** <ul>
       
  5305 ** <li>  SQLITE_MUTEX_FAST
       
  5306 ** <li>  SQLITE_MUTEX_RECURSIVE
       
  5307 ** <li>  SQLITE_MUTEX_STATIC_MASTER
       
  5308 ** <li>  SQLITE_MUTEX_STATIC_MEM
       
  5309 ** <li>  SQLITE_MUTEX_STATIC_MEM2
       
  5310 ** <li>  SQLITE_MUTEX_STATIC_PRNG
       
  5311 ** <li>  SQLITE_MUTEX_STATIC_LRU
       
  5312 ** <li>  SQLITE_MUTEX_STATIC_LRU2
       
  5313 ** </ul>)^
       
  5314 **
       
  5315 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
       
  5316 ** cause sqlite3_mutex_alloc() to create
       
  5317 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
       
  5318 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
       
  5319 ** The mutex implementation does not need to make a distinction
       
  5320 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
       
  5321 ** not want to.  ^SQLite will only request a recursive mutex in
       
  5322 ** cases where it really needs one.  ^If a faster non-recursive mutex
       
  5323 ** implementation is available on the host platform, the mutex subsystem
       
  5324 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
       
  5325 **
       
  5326 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
       
  5327 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
       
  5328 ** a pointer to a static preexisting mutex.  ^Six static mutexes are
       
  5329 ** used by the current version of SQLite.  Future versions of SQLite
       
  5330 ** may add additional static mutexes.  Static mutexes are for internal
       
  5331 ** use by SQLite only.  Applications that use SQLite mutexes should
       
  5332 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
       
  5333 ** SQLITE_MUTEX_RECURSIVE.
       
  5334 **
       
  5335 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
       
  5336 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
       
  5337 ** returns a different mutex on every call.  ^But for the static
       
  5338 ** mutex types, the same mutex is returned on every call that has
       
  5339 ** the same type number.
       
  5340 **
       
  5341 ** ^The sqlite3_mutex_free() routine deallocates a previously
       
  5342 ** allocated dynamic mutex.  ^SQLite is careful to deallocate every
       
  5343 ** dynamic mutex that it allocates.  The dynamic mutexes must not be in
       
  5344 ** use when they are deallocated.  Attempting to deallocate a static
       
  5345 ** mutex results in undefined behavior.  ^SQLite never deallocates
       
  5346 ** a static mutex.
       
  5347 **
       
  5348 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
       
  5349 ** to enter a mutex.  ^If another thread is already within the mutex,
       
  5350 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
       
  5351 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
       
  5352 ** upon successful entry.  ^(Mutexes created using
       
  5353 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
       
  5354 ** In such cases the,
       
  5355 ** mutex must be exited an equal number of times before another thread
       
  5356 ** can enter.)^  ^(If the same thread tries to enter any other
       
  5357 ** kind of mutex more than once, the behavior is undefined.
       
  5358 ** SQLite will never exhibit
       
  5359 ** such behavior in its own use of mutexes.)^
       
  5360 **
       
  5361 ** ^(Some systems (for example, Windows 95) do not support the operation
       
  5362 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
       
  5363 ** will always return SQLITE_BUSY.  The SQLite core only ever uses
       
  5364 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
       
  5365 **
       
  5366 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
       
  5367 ** previously entered by the same thread.   ^(The behavior
       
  5368 ** is undefined if the mutex is not currently entered by the
       
  5369 ** calling thread or is not currently allocated.  SQLite will
       
  5370 ** never do either.)^
       
  5371 **
       
  5372 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
       
  5373 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
       
  5374 ** behave as no-ops.
       
  5375 **
       
  5376 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
       
  5377 */
       
  5378 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
       
  5379 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
       
  5380 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
       
  5381 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
       
  5382 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
       
  5383 
       
  5384 /*
       
  5385 ** CAPI3REF: Mutex Methods Object
       
  5386 **
       
  5387 ** An instance of this structure defines the low-level routines
       
  5388 ** used to allocate and use mutexes.
       
  5389 **
       
  5390 ** Usually, the default mutex implementations provided by SQLite are
       
  5391 ** sufficient, however the user has the option of substituting a custom
       
  5392 ** implementation for specialized deployments or systems for which SQLite
       
  5393 ** does not provide a suitable implementation. In this case, the user
       
  5394 ** creates and populates an instance of this structure to pass
       
  5395 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
       
  5396 ** Additionally, an instance of this structure can be used as an
       
  5397 ** output variable when querying the system for the current mutex
       
  5398 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
       
  5399 **
       
  5400 ** ^The xMutexInit method defined by this structure is invoked as
       
  5401 ** part of system initialization by the sqlite3_initialize() function.
       
  5402 ** ^The xMutexInit routine is called by SQLite exactly once for each
       
  5403 ** effective call to [sqlite3_initialize()].
       
  5404 **
       
  5405 ** ^The xMutexEnd method defined by this structure is invoked as
       
  5406 ** part of system shutdown by the sqlite3_shutdown() function. The
       
  5407 ** implementation of this method is expected to release all outstanding
       
  5408 ** resources obtained by the mutex methods implementation, especially
       
  5409 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
       
  5410 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
       
  5411 **
       
  5412 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
       
  5413 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
       
  5414 ** xMutexNotheld) implement the following interfaces (respectively):
       
  5415 **
       
  5416 ** <ul>
       
  5417 **   <li>  [sqlite3_mutex_alloc()] </li>
       
  5418 **   <li>  [sqlite3_mutex_free()] </li>
       
  5419 **   <li>  [sqlite3_mutex_enter()] </li>
       
  5420 **   <li>  [sqlite3_mutex_try()] </li>
       
  5421 **   <li>  [sqlite3_mutex_leave()] </li>
       
  5422 **   <li>  [sqlite3_mutex_held()] </li>
       
  5423 **   <li>  [sqlite3_mutex_notheld()] </li>
       
  5424 ** </ul>)^
       
  5425 **
       
  5426 ** The only difference is that the public sqlite3_XXX functions enumerated
       
  5427 ** above silently ignore any invocations that pass a NULL pointer instead
       
  5428 ** of a valid mutex handle. The implementations of the methods defined
       
  5429 ** by this structure are not required to handle this case, the results
       
  5430 ** of passing a NULL pointer instead of a valid mutex handle are undefined
       
  5431 ** (i.e. it is acceptable to provide an implementation that segfaults if
       
  5432 ** it is passed a NULL pointer).
       
  5433 **
       
  5434 ** The xMutexInit() method must be threadsafe.  ^It must be harmless to
       
  5435 ** invoke xMutexInit() multiple times within the same process and without
       
  5436 ** intervening calls to xMutexEnd().  Second and subsequent calls to
       
  5437 ** xMutexInit() must be no-ops.
       
  5438 **
       
  5439 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
       
  5440 ** and its associates).  ^Similarly, xMutexAlloc() must not use SQLite memory
       
  5441 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
       
  5442 ** memory allocation for a fast or recursive mutex.
       
  5443 **
       
  5444 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
       
  5445 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
       
  5446 ** If xMutexInit fails in any way, it is expected to clean up after itself
       
  5447 ** prior to returning.
       
  5448 */
       
  5449 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
       
  5450 struct sqlite3_mutex_methods {
       
  5451   int (*xMutexInit)(void);
       
  5452   int (*xMutexEnd)(void);
       
  5453   sqlite3_mutex *(*xMutexAlloc)(int);
       
  5454   void (*xMutexFree)(sqlite3_mutex *);
       
  5455   void (*xMutexEnter)(sqlite3_mutex *);
       
  5456   int (*xMutexTry)(sqlite3_mutex *);
       
  5457   void (*xMutexLeave)(sqlite3_mutex *);
       
  5458   int (*xMutexHeld)(sqlite3_mutex *);
       
  5459   int (*xMutexNotheld)(sqlite3_mutex *);
       
  5460 };
       
  5461 
       
  5462 /*
       
  5463 ** CAPI3REF: Mutex Verification Routines
       
  5464 **
       
  5465 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
       
  5466 ** are intended for use inside assert() statements.  ^The SQLite core
       
  5467 ** never uses these routines except inside an assert() and applications
       
  5468 ** are advised to follow the lead of the core.  ^The SQLite core only
       
  5469 ** provides implementations for these routines when it is compiled
       
  5470 ** with the SQLITE_DEBUG flag.  ^External mutex implementations
       
  5471 ** are only required to provide these routines if SQLITE_DEBUG is
       
  5472 ** defined and if NDEBUG is not defined.
       
  5473 **
       
  5474 ** ^These routines should return true if the mutex in their argument
       
  5475 ** is held or not held, respectively, by the calling thread.
       
  5476 **
       
  5477 ** ^The implementation is not required to provided versions of these
       
  5478 ** routines that actually work. If the implementation does not provide working
       
  5479 ** versions of these routines, it should at least provide stubs that always
       
  5480 ** return true so that one does not get spurious assertion failures.
       
  5481 **
       
  5482 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
       
  5483 ** the routine should return 1.   This seems counter-intuitive since
       
  5484 ** clearly the mutex cannot be held if it does not exist.  But
       
  5485 ** the reason the mutex does not exist is because the build is not
       
  5486 ** using mutexes.  And we do not want the assert() containing the
       
  5487 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
       
  5488 ** the appropriate thing to do.  ^The sqlite3_mutex_notheld()
       
  5489 ** interface should also return 1 when given a NULL pointer.
       
  5490 */
       
  5491 #ifndef NDEBUG
       
  5492 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
       
  5493 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
       
  5494 #endif
       
  5495 
       
  5496 /*
       
  5497 ** CAPI3REF: Mutex Types
       
  5498 **
       
  5499 ** The [sqlite3_mutex_alloc()] interface takes a single argument
       
  5500 ** which is one of these integer constants.
       
  5501 **
       
  5502 ** The set of static mutexes may change from one SQLite release to the
       
  5503 ** next.  Applications that override the built-in mutex logic must be
       
  5504 ** prepared to accommodate additional static mutexes.
       
  5505 */
       
  5506 #define SQLITE_MUTEX_FAST             0
       
  5507 #define SQLITE_MUTEX_RECURSIVE        1
       
  5508 #define SQLITE_MUTEX_STATIC_MASTER    2
       
  5509 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
       
  5510 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
       
  5511 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
       
  5512 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
       
  5513 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
       
  5514 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
       
  5515 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
       
  5516 
       
  5517 /*
       
  5518 ** CAPI3REF: Retrieve the mutex for a database connection
       
  5519 **
       
  5520 ** ^This interface returns a pointer the [sqlite3_mutex] object that 
       
  5521 ** serializes access to the [database connection] given in the argument
       
  5522 ** when the [threading mode] is Serialized.
       
  5523 ** ^If the [threading mode] is Single-thread or Multi-thread then this
       
  5524 ** routine returns a NULL pointer.
       
  5525 */
       
  5526 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
       
  5527 
       
  5528 /*
       
  5529 ** CAPI3REF: Low-Level Control Of Database Files
       
  5530 **
       
  5531 ** ^The [sqlite3_file_control()] interface makes a direct call to the
       
  5532 ** xFileControl method for the [sqlite3_io_methods] object associated
       
  5533 ** with a particular database identified by the second argument. ^The
       
  5534 ** name of the database is "main" for the main database or "temp" for the
       
  5535 ** TEMP database, or the name that appears after the AS keyword for
       
  5536 ** databases that are added using the [ATTACH] SQL command.
       
  5537 ** ^A NULL pointer can be used in place of "main" to refer to the
       
  5538 ** main database file.
       
  5539 ** ^The third and fourth parameters to this routine
       
  5540 ** are passed directly through to the second and third parameters of
       
  5541 ** the xFileControl method.  ^The return value of the xFileControl
       
  5542 ** method becomes the return value of this routine.
       
  5543 **
       
  5544 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
       
  5545 ** a pointer to the underlying [sqlite3_file] object to be written into
       
  5546 ** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
       
  5547 ** case is a short-circuit path which does not actually invoke the
       
  5548 ** underlying sqlite3_io_methods.xFileControl method.
       
  5549 **
       
  5550 ** ^If the second parameter (zDbName) does not match the name of any
       
  5551 ** open database file, then SQLITE_ERROR is returned.  ^This error
       
  5552 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
       
  5553 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
       
  5554 ** also return SQLITE_ERROR.  There is no way to distinguish between
       
  5555 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
       
  5556 ** xFileControl method.
       
  5557 **
       
  5558 ** See also: [SQLITE_FCNTL_LOCKSTATE]
       
  5559 */
       
  5560 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
       
  5561 
       
  5562 /*
       
  5563 ** CAPI3REF: Testing Interface
       
  5564 **
       
  5565 ** ^The sqlite3_test_control() interface is used to read out internal
       
  5566 ** state of SQLite and to inject faults into SQLite for testing
       
  5567 ** purposes.  ^The first parameter is an operation code that determines
       
  5568 ** the number, meaning, and operation of all subsequent parameters.
       
  5569 **
       
  5570 ** This interface is not for use by applications.  It exists solely
       
  5571 ** for verifying the correct operation of the SQLite library.  Depending
       
  5572 ** on how the SQLite library is compiled, this interface might not exist.
       
  5573 **
       
  5574 ** The details of the operation codes, their meanings, the parameters
       
  5575 ** they take, and what they do are all subject to change without notice.
       
  5576 ** Unlike most of the SQLite API, this function is not guaranteed to
       
  5577 ** operate consistently from one release to the next.
       
  5578 */
       
  5579 SQLITE_API int sqlite3_test_control(int op, ...);
       
  5580 
       
  5581 /*
       
  5582 ** CAPI3REF: Testing Interface Operation Codes
       
  5583 **
       
  5584 ** These constants are the valid operation code parameters used
       
  5585 ** as the first argument to [sqlite3_test_control()].
       
  5586 **
       
  5587 ** These parameters and their meanings are subject to change
       
  5588 ** without notice.  These values are for testing purposes only.
       
  5589 ** Applications should not use any of these parameters or the
       
  5590 ** [sqlite3_test_control()] interface.
       
  5591 */
       
  5592 #define SQLITE_TESTCTRL_FIRST                    5
       
  5593 #define SQLITE_TESTCTRL_PRNG_SAVE                5
       
  5594 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
       
  5595 #define SQLITE_TESTCTRL_PRNG_RESET               7
       
  5596 #define SQLITE_TESTCTRL_BITVEC_TEST              8
       
  5597 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
       
  5598 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
       
  5599 #define SQLITE_TESTCTRL_PENDING_BYTE            11
       
  5600 #define SQLITE_TESTCTRL_ASSERT                  12
       
  5601 #define SQLITE_TESTCTRL_ALWAYS                  13
       
  5602 #define SQLITE_TESTCTRL_RESERVE                 14
       
  5603 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
       
  5604 #define SQLITE_TESTCTRL_ISKEYWORD               16
       
  5605 #define SQLITE_TESTCTRL_PGHDRSZ                 17
       
  5606 #define SQLITE_TESTCTRL_SCRATCHMALLOC           18
       
  5607 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         19
       
  5608 #define SQLITE_TESTCTRL_LAST                    19
       
  5609 
       
  5610 /*
       
  5611 ** CAPI3REF: SQLite Runtime Status
       
  5612 **
       
  5613 ** ^This interface is used to retrieve runtime status information
       
  5614 ** about the performance of SQLite, and optionally to reset various
       
  5615 ** highwater marks.  ^The first argument is an integer code for
       
  5616 ** the specific parameter to measure.  ^(Recognized integer codes
       
  5617 ** are of the form [status parameters | SQLITE_STATUS_...].)^
       
  5618 ** ^The current value of the parameter is returned into *pCurrent.
       
  5619 ** ^The highest recorded value is returned in *pHighwater.  ^If the
       
  5620 ** resetFlag is true, then the highest record value is reset after
       
  5621 ** *pHighwater is written.  ^(Some parameters do not record the highest
       
  5622 ** value.  For those parameters
       
  5623 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
       
  5624 ** ^(Other parameters record only the highwater mark and not the current
       
  5625 ** value.  For these latter parameters nothing is written into *pCurrent.)^
       
  5626 **
       
  5627 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
       
  5628 ** non-zero [error code] on failure.
       
  5629 **
       
  5630 ** This routine is threadsafe but is not atomic.  This routine can be
       
  5631 ** called while other threads are running the same or different SQLite
       
  5632 ** interfaces.  However the values returned in *pCurrent and
       
  5633 ** *pHighwater reflect the status of SQLite at different points in time
       
  5634 ** and it is possible that another thread might change the parameter
       
  5635 ** in between the times when *pCurrent and *pHighwater are written.
       
  5636 **
       
  5637 ** See also: [sqlite3_db_status()]
       
  5638 */
       
  5639 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
       
  5640 
       
  5641 
       
  5642 /*
       
  5643 ** CAPI3REF: Status Parameters
       
  5644 ** KEYWORDS: {status parameters}
       
  5645 **
       
  5646 ** These integer constants designate various run-time status parameters
       
  5647 ** that can be returned by [sqlite3_status()].
       
  5648 **
       
  5649 ** <dl>
       
  5650 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
       
  5651 ** <dd>This parameter is the current amount of memory checked out
       
  5652 ** using [sqlite3_malloc()], either directly or indirectly.  The
       
  5653 ** figure includes calls made to [sqlite3_malloc()] by the application
       
  5654 ** and internal memory usage by the SQLite library.  Scratch memory
       
  5655 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
       
  5656 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
       
  5657 ** this parameter.  The amount returned is the sum of the allocation
       
  5658 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
       
  5659 **
       
  5660 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
       
  5661 ** <dd>This parameter records the largest memory allocation request
       
  5662 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
       
  5663 ** internal equivalents).  Only the value returned in the
       
  5664 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  5665 ** The value written into the *pCurrent parameter is undefined.</dd>)^
       
  5666 **
       
  5667 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
       
  5668 ** <dd>This parameter records the number of separate memory allocations
       
  5669 ** currently checked out.</dd>)^
       
  5670 **
       
  5671 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
       
  5672 ** <dd>This parameter returns the number of pages used out of the
       
  5673 ** [pagecache memory allocator] that was configured using 
       
  5674 ** [SQLITE_CONFIG_PAGECACHE].  The
       
  5675 ** value returned is in pages, not in bytes.</dd>)^
       
  5676 **
       
  5677 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 
       
  5678 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
       
  5679 ** <dd>This parameter returns the number of bytes of page cache
       
  5680 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
       
  5681 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
       
  5682 ** returned value includes allocations that overflowed because they
       
  5683 ** where too large (they were larger than the "sz" parameter to
       
  5684 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
       
  5685 ** no space was left in the page cache.</dd>)^
       
  5686 **
       
  5687 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
       
  5688 ** <dd>This parameter records the largest memory allocation request
       
  5689 ** handed to [pagecache memory allocator].  Only the value returned in the
       
  5690 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  5691 ** The value written into the *pCurrent parameter is undefined.</dd>)^
       
  5692 **
       
  5693 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
       
  5694 ** <dd>This parameter returns the number of allocations used out of the
       
  5695 ** [scratch memory allocator] configured using
       
  5696 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
       
  5697 ** in bytes.  Since a single thread may only have one scratch allocation
       
  5698 ** outstanding at time, this parameter also reports the number of threads
       
  5699 ** using scratch memory at the same time.</dd>)^
       
  5700 **
       
  5701 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
       
  5702 ** <dd>This parameter returns the number of bytes of scratch memory
       
  5703 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
       
  5704 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
       
  5705 ** returned include overflows because the requested allocation was too
       
  5706 ** larger (that is, because the requested allocation was larger than the
       
  5707 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
       
  5708 ** slots were available.
       
  5709 ** </dd>)^
       
  5710 **
       
  5711 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
       
  5712 ** <dd>This parameter records the largest memory allocation request
       
  5713 ** handed to [scratch memory allocator].  Only the value returned in the
       
  5714 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  5715 ** The value written into the *pCurrent parameter is undefined.</dd>)^
       
  5716 **
       
  5717 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
       
  5718 ** <dd>This parameter records the deepest parser stack.  It is only
       
  5719 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
       
  5720 ** </dl>
       
  5721 **
       
  5722 ** New status parameters may be added from time to time.
       
  5723 */
       
  5724 #define SQLITE_STATUS_MEMORY_USED          0
       
  5725 #define SQLITE_STATUS_PAGECACHE_USED       1
       
  5726 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
       
  5727 #define SQLITE_STATUS_SCRATCH_USED         3
       
  5728 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4
       
  5729 #define SQLITE_STATUS_MALLOC_SIZE          5
       
  5730 #define SQLITE_STATUS_PARSER_STACK         6
       
  5731 #define SQLITE_STATUS_PAGECACHE_SIZE       7
       
  5732 #define SQLITE_STATUS_SCRATCH_SIZE         8
       
  5733 #define SQLITE_STATUS_MALLOC_COUNT         9
       
  5734 
       
  5735 /*
       
  5736 ** CAPI3REF: Database Connection Status
       
  5737 **
       
  5738 ** ^This interface is used to retrieve runtime status information 
       
  5739 ** about a single [database connection].  ^The first argument is the
       
  5740 ** database connection object to be interrogated.  ^The second argument
       
  5741 ** is an integer constant, taken from the set of
       
  5742 ** [SQLITE_DBSTATUS options], that
       
  5743 ** determines the parameter to interrogate.  The set of 
       
  5744 ** [SQLITE_DBSTATUS options] is likely
       
  5745 ** to grow in future releases of SQLite.
       
  5746 **
       
  5747 ** ^The current value of the requested parameter is written into *pCur
       
  5748 ** and the highest instantaneous value is written into *pHiwtr.  ^If
       
  5749 ** the resetFlg is true, then the highest instantaneous value is
       
  5750 ** reset back down to the current value.
       
  5751 **
       
  5752 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
       
  5753 ** non-zero [error code] on failure.
       
  5754 **
       
  5755 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
       
  5756 */
       
  5757 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
       
  5758 
       
  5759 /*
       
  5760 ** CAPI3REF: Status Parameters for database connections
       
  5761 ** KEYWORDS: {SQLITE_DBSTATUS options}
       
  5762 **
       
  5763 ** These constants are the available integer "verbs" that can be passed as
       
  5764 ** the second argument to the [sqlite3_db_status()] interface.
       
  5765 **
       
  5766 ** New verbs may be added in future releases of SQLite. Existing verbs
       
  5767 ** might be discontinued. Applications should check the return code from
       
  5768 ** [sqlite3_db_status()] to make sure that the call worked.
       
  5769 ** The [sqlite3_db_status()] interface will return a non-zero error code
       
  5770 ** if a discontinued or unsupported verb is invoked.
       
  5771 **
       
  5772 ** <dl>
       
  5773 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
       
  5774 ** <dd>This parameter returns the number of lookaside memory slots currently
       
  5775 ** checked out.</dd>)^
       
  5776 **
       
  5777 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
       
  5778 ** <dd>This parameter returns the number malloc attempts that were 
       
  5779 ** satisfied using lookaside memory. Only the high-water value is meaningful;
       
  5780 ** the current value is always zero.)^
       
  5781 **
       
  5782 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
       
  5783 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
       
  5784 ** <dd>This parameter returns the number malloc attempts that might have
       
  5785 ** been satisfied using lookaside memory but failed due to the amount of
       
  5786 ** memory requested being larger than the lookaside slot size.
       
  5787 ** Only the high-water value is meaningful;
       
  5788 ** the current value is always zero.)^
       
  5789 **
       
  5790 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
       
  5791 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
       
  5792 ** <dd>This parameter returns the number malloc attempts that might have
       
  5793 ** been satisfied using lookaside memory but failed due to all lookaside
       
  5794 ** memory already being in use.
       
  5795 ** Only the high-water value is meaningful;
       
  5796 ** the current value is always zero.)^
       
  5797 **
       
  5798 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
       
  5799 ** <dd>This parameter returns the approximate number of of bytes of heap
       
  5800 ** memory used by all pager caches associated with the database connection.)^
       
  5801 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
       
  5802 **
       
  5803 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
       
  5804 ** <dd>This parameter returns the approximate number of of bytes of heap
       
  5805 ** memory used to store the schema for all databases associated
       
  5806 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 
       
  5807 ** ^The full amount of memory used by the schemas is reported, even if the
       
  5808 ** schema memory is shared with other database connections due to
       
  5809 ** [shared cache mode] being enabled.
       
  5810 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
       
  5811 **
       
  5812 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
       
  5813 ** <dd>This parameter returns the approximate number of of bytes of heap
       
  5814 ** and lookaside memory used by all prepared statements associated with
       
  5815 ** the database connection.)^
       
  5816 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
       
  5817 ** </dd>
       
  5818 ** </dl>
       
  5819 */
       
  5820 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
       
  5821 #define SQLITE_DBSTATUS_CACHE_USED           1
       
  5822 #define SQLITE_DBSTATUS_SCHEMA_USED          2
       
  5823 #define SQLITE_DBSTATUS_STMT_USED            3
       
  5824 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
       
  5825 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
       
  5826 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
       
  5827 #define SQLITE_DBSTATUS_MAX                  6   /* Largest defined DBSTATUS */
       
  5828 
       
  5829 
       
  5830 /*
       
  5831 ** CAPI3REF: Prepared Statement Status
       
  5832 **
       
  5833 ** ^(Each prepared statement maintains various
       
  5834 ** [SQLITE_STMTSTATUS counters] that measure the number
       
  5835 ** of times it has performed specific operations.)^  These counters can
       
  5836 ** be used to monitor the performance characteristics of the prepared
       
  5837 ** statements.  For example, if the number of table steps greatly exceeds
       
  5838 ** the number of table searches or result rows, that would tend to indicate
       
  5839 ** that the prepared statement is using a full table scan rather than
       
  5840 ** an index.  
       
  5841 **
       
  5842 ** ^(This interface is used to retrieve and reset counter values from
       
  5843 ** a [prepared statement].  The first argument is the prepared statement
       
  5844 ** object to be interrogated.  The second argument
       
  5845 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
       
  5846 ** to be interrogated.)^
       
  5847 ** ^The current value of the requested counter is returned.
       
  5848 ** ^If the resetFlg is true, then the counter is reset to zero after this
       
  5849 ** interface call returns.
       
  5850 **
       
  5851 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
       
  5852 */
       
  5853 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
       
  5854 
       
  5855 /*
       
  5856 ** CAPI3REF: Status Parameters for prepared statements
       
  5857 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
       
  5858 **
       
  5859 ** These preprocessor macros define integer codes that name counter
       
  5860 ** values associated with the [sqlite3_stmt_status()] interface.
       
  5861 ** The meanings of the various counters are as follows:
       
  5862 **
       
  5863 ** <dl>
       
  5864 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
       
  5865 ** <dd>^This is the number of times that SQLite has stepped forward in
       
  5866 ** a table as part of a full table scan.  Large numbers for this counter
       
  5867 ** may indicate opportunities for performance improvement through 
       
  5868 ** careful use of indices.</dd>
       
  5869 **
       
  5870 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
       
  5871 ** <dd>^This is the number of sort operations that have occurred.
       
  5872 ** A non-zero value in this counter may indicate an opportunity to
       
  5873 ** improvement performance through careful use of indices.</dd>
       
  5874 **
       
  5875 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
       
  5876 ** <dd>^This is the number of rows inserted into transient indices that
       
  5877 ** were created automatically in order to help joins run faster.
       
  5878 ** A non-zero value in this counter may indicate an opportunity to
       
  5879 ** improvement performance by adding permanent indices that do not
       
  5880 ** need to be reinitialized each time the statement is run.</dd>
       
  5881 **
       
  5882 ** </dl>
       
  5883 */
       
  5884 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
       
  5885 #define SQLITE_STMTSTATUS_SORT              2
       
  5886 #define SQLITE_STMTSTATUS_AUTOINDEX         3
       
  5887 
       
  5888 /*
       
  5889 ** CAPI3REF: Custom Page Cache Object
       
  5890 **
       
  5891 ** The sqlite3_pcache type is opaque.  It is implemented by
       
  5892 ** the pluggable module.  The SQLite core has no knowledge of
       
  5893 ** its size or internal structure and never deals with the
       
  5894 ** sqlite3_pcache object except by holding and passing pointers
       
  5895 ** to the object.
       
  5896 **
       
  5897 ** See [sqlite3_pcache_methods] for additional information.
       
  5898 */
       
  5899 typedef struct sqlite3_pcache sqlite3_pcache;
       
  5900 
       
  5901 /*
       
  5902 ** CAPI3REF: Application Defined Page Cache.
       
  5903 ** KEYWORDS: {page cache}
       
  5904 **
       
  5905 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
       
  5906 ** register an alternative page cache implementation by passing in an 
       
  5907 ** instance of the sqlite3_pcache_methods structure.)^
       
  5908 ** In many applications, most of the heap memory allocated by 
       
  5909 ** SQLite is used for the page cache.
       
  5910 ** By implementing a 
       
  5911 ** custom page cache using this API, an application can better control
       
  5912 ** the amount of memory consumed by SQLite, the way in which 
       
  5913 ** that memory is allocated and released, and the policies used to 
       
  5914 ** determine exactly which parts of a database file are cached and for 
       
  5915 ** how long.
       
  5916 **
       
  5917 ** The alternative page cache mechanism is an
       
  5918 ** extreme measure that is only needed by the most demanding applications.
       
  5919 ** The built-in page cache is recommended for most uses.
       
  5920 **
       
  5921 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an
       
  5922 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
       
  5923 ** the application may discard the parameter after the call to
       
  5924 ** [sqlite3_config()] returns.)^
       
  5925 **
       
  5926 ** [[the xInit() page cache method]]
       
  5927 ** ^(The xInit() method is called once for each effective 
       
  5928 ** call to [sqlite3_initialize()])^
       
  5929 ** (usually only once during the lifetime of the process). ^(The xInit()
       
  5930 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^
       
  5931 ** The intent of the xInit() method is to set up global data structures 
       
  5932 ** required by the custom page cache implementation. 
       
  5933 ** ^(If the xInit() method is NULL, then the 
       
  5934 ** built-in default page cache is used instead of the application defined
       
  5935 ** page cache.)^
       
  5936 **
       
  5937 ** [[the xShutdown() page cache method]]
       
  5938 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
       
  5939 ** It can be used to clean up 
       
  5940 ** any outstanding resources before process shutdown, if required.
       
  5941 ** ^The xShutdown() method may be NULL.
       
  5942 **
       
  5943 ** ^SQLite automatically serializes calls to the xInit method,
       
  5944 ** so the xInit method need not be threadsafe.  ^The
       
  5945 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
       
  5946 ** not need to be threadsafe either.  All other methods must be threadsafe
       
  5947 ** in multithreaded applications.
       
  5948 **
       
  5949 ** ^SQLite will never invoke xInit() more than once without an intervening
       
  5950 ** call to xShutdown().
       
  5951 **
       
  5952 ** [[the xCreate() page cache methods]]
       
  5953 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
       
  5954 ** SQLite will typically create one cache instance for each open database file,
       
  5955 ** though this is not guaranteed. ^The
       
  5956 ** first parameter, szPage, is the size in bytes of the pages that must
       
  5957 ** be allocated by the cache.  ^szPage will not be a power of two.  ^szPage
       
  5958 ** will the page size of the database file that is to be cached plus an
       
  5959 ** increment (here called "R") of less than 250.  SQLite will use the
       
  5960 ** extra R bytes on each page to store metadata about the underlying
       
  5961 ** database page on disk.  The value of R depends
       
  5962 ** on the SQLite version, the target platform, and how SQLite was compiled.
       
  5963 ** ^(R is constant for a particular build of SQLite. Except, there are two
       
  5964 ** distinct values of R when SQLite is compiled with the proprietary
       
  5965 ** ZIPVFS extension.)^  ^The second argument to
       
  5966 ** xCreate(), bPurgeable, is true if the cache being created will
       
  5967 ** be used to cache database pages of a file stored on disk, or
       
  5968 ** false if it is used for an in-memory database. The cache implementation
       
  5969 ** does not have to do anything special based with the value of bPurgeable;
       
  5970 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
       
  5971 ** never invoke xUnpin() except to deliberately delete a page.
       
  5972 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
       
  5973 ** false will always have the "discard" flag set to true.  
       
  5974 ** ^Hence, a cache created with bPurgeable false will
       
  5975 ** never contain any unpinned pages.
       
  5976 **
       
  5977 ** [[the xCachesize() page cache method]]
       
  5978 ** ^(The xCachesize() method may be called at any time by SQLite to set the
       
  5979 ** suggested maximum cache-size (number of pages stored by) the cache
       
  5980 ** instance passed as the first argument. This is the value configured using
       
  5981 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
       
  5982 ** parameter, the implementation is not required to do anything with this
       
  5983 ** value; it is advisory only.
       
  5984 **
       
  5985 ** [[the xPagecount() page cache methods]]
       
  5986 ** The xPagecount() method must return the number of pages currently
       
  5987 ** stored in the cache, both pinned and unpinned.
       
  5988 ** 
       
  5989 ** [[the xFetch() page cache methods]]
       
  5990 ** The xFetch() method locates a page in the cache and returns a pointer to 
       
  5991 ** the page, or a NULL pointer.
       
  5992 ** A "page", in this context, means a buffer of szPage bytes aligned at an
       
  5993 ** 8-byte boundary. The page to be fetched is determined by the key. ^The
       
  5994 ** minimum key value is 1.  After it has been retrieved using xFetch, the page 
       
  5995 ** is considered to be "pinned".
       
  5996 **
       
  5997 ** If the requested page is already in the page cache, then the page cache
       
  5998 ** implementation must return a pointer to the page buffer with its content
       
  5999 ** intact.  If the requested page is not already in the cache, then the
       
  6000 ** cache implementation should use the value of the createFlag
       
  6001 ** parameter to help it determined what action to take:
       
  6002 **
       
  6003 ** <table border=1 width=85% align=center>
       
  6004 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
       
  6005 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
       
  6006 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
       
  6007 **                 Otherwise return NULL.
       
  6008 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
       
  6009 **                 NULL if allocating a new page is effectively impossible.
       
  6010 ** </table>
       
  6011 **
       
  6012 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
       
  6013 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
       
  6014 ** failed.)^  In between the to xFetch() calls, SQLite may
       
  6015 ** attempt to unpin one or more cache pages by spilling the content of
       
  6016 ** pinned pages to disk and synching the operating system disk cache.
       
  6017 **
       
  6018 ** [[the xUnpin() page cache method]]
       
  6019 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
       
  6020 ** as its second argument.  If the third parameter, discard, is non-zero,
       
  6021 ** then the page must be evicted from the cache.
       
  6022 ** ^If the discard parameter is
       
  6023 ** zero, then the page may be discarded or retained at the discretion of
       
  6024 ** page cache implementation. ^The page cache implementation
       
  6025 ** may choose to evict unpinned pages at any time.
       
  6026 **
       
  6027 ** The cache must not perform any reference counting. A single 
       
  6028 ** call to xUnpin() unpins the page regardless of the number of prior calls 
       
  6029 ** to xFetch().
       
  6030 **
       
  6031 ** [[the xRekey() page cache methods]]
       
  6032 ** The xRekey() method is used to change the key value associated with the
       
  6033 ** page passed as the second argument. If the cache
       
  6034 ** previously contains an entry associated with newKey, it must be
       
  6035 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
       
  6036 ** to be pinned.
       
  6037 **
       
  6038 ** When SQLite calls the xTruncate() method, the cache must discard all
       
  6039 ** existing cache entries with page numbers (keys) greater than or equal
       
  6040 ** to the value of the iLimit parameter passed to xTruncate(). If any
       
  6041 ** of these pages are pinned, they are implicitly unpinned, meaning that
       
  6042 ** they can be safely discarded.
       
  6043 **
       
  6044 ** [[the xDestroy() page cache method]]
       
  6045 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
       
  6046 ** All resources associated with the specified cache should be freed. ^After
       
  6047 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
       
  6048 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
       
  6049 ** functions.
       
  6050 */
       
  6051 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
       
  6052 struct sqlite3_pcache_methods {
       
  6053   void *pArg;
       
  6054   int (*xInit)(void*);
       
  6055   void (*xShutdown)(void*);
       
  6056   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
       
  6057   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
       
  6058   int (*xPagecount)(sqlite3_pcache*);
       
  6059   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
       
  6060   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
       
  6061   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
       
  6062   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
       
  6063   void (*xDestroy)(sqlite3_pcache*);
       
  6064 };
       
  6065 
       
  6066 /*
       
  6067 ** CAPI3REF: Online Backup Object
       
  6068 **
       
  6069 ** The sqlite3_backup object records state information about an ongoing
       
  6070 ** online backup operation.  ^The sqlite3_backup object is created by
       
  6071 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
       
  6072 ** [sqlite3_backup_finish()].
       
  6073 **
       
  6074 ** See Also: [Using the SQLite Online Backup API]
       
  6075 */
       
  6076 typedef struct sqlite3_backup sqlite3_backup;
       
  6077 
       
  6078 /*
       
  6079 ** CAPI3REF: Online Backup API.
       
  6080 **
       
  6081 ** The backup API copies the content of one database into another.
       
  6082 ** It is useful either for creating backups of databases or
       
  6083 ** for copying in-memory databases to or from persistent files. 
       
  6084 **
       
  6085 ** See Also: [Using the SQLite Online Backup API]
       
  6086 **
       
  6087 ** ^SQLite holds a write transaction open on the destination database file
       
  6088 ** for the duration of the backup operation.
       
  6089 ** ^The source database is read-locked only while it is being read;
       
  6090 ** it is not locked continuously for the entire backup operation.
       
  6091 ** ^Thus, the backup may be performed on a live source database without
       
  6092 ** preventing other database connections from
       
  6093 ** reading or writing to the source database while the backup is underway.
       
  6094 ** 
       
  6095 ** ^(To perform a backup operation: 
       
  6096 **   <ol>
       
  6097 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
       
  6098 **         backup, 
       
  6099 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
       
  6100 **         the data between the two databases, and finally
       
  6101 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
       
  6102 **         associated with the backup operation. 
       
  6103 **   </ol>)^
       
  6104 ** There should be exactly one call to sqlite3_backup_finish() for each
       
  6105 ** successful call to sqlite3_backup_init().
       
  6106 **
       
  6107 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
       
  6108 **
       
  6109 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 
       
  6110 ** [database connection] associated with the destination database 
       
  6111 ** and the database name, respectively.
       
  6112 ** ^The database name is "main" for the main database, "temp" for the
       
  6113 ** temporary database, or the name specified after the AS keyword in
       
  6114 ** an [ATTACH] statement for an attached database.
       
  6115 ** ^The S and M arguments passed to 
       
  6116 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
       
  6117 ** and database name of the source database, respectively.
       
  6118 ** ^The source and destination [database connections] (parameters S and D)
       
  6119 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
       
  6120 ** an error.
       
  6121 **
       
  6122 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
       
  6123 ** returned and an error code and error message are stored in the
       
  6124 ** destination [database connection] D.
       
  6125 ** ^The error code and message for the failed call to sqlite3_backup_init()
       
  6126 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
       
  6127 ** [sqlite3_errmsg16()] functions.
       
  6128 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
       
  6129 ** [sqlite3_backup] object.
       
  6130 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
       
  6131 ** sqlite3_backup_finish() functions to perform the specified backup 
       
  6132 ** operation.
       
  6133 **
       
  6134 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
       
  6135 **
       
  6136 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 
       
  6137 ** the source and destination databases specified by [sqlite3_backup] object B.
       
  6138 ** ^If N is negative, all remaining source pages are copied. 
       
  6139 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
       
  6140 ** are still more pages to be copied, then the function returns [SQLITE_OK].
       
  6141 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
       
  6142 ** from source to destination, then it returns [SQLITE_DONE].
       
  6143 ** ^If an error occurs while running sqlite3_backup_step(B,N),
       
  6144 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
       
  6145 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
       
  6146 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
       
  6147 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
       
  6148 **
       
  6149 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
       
  6150 ** <ol>
       
  6151 ** <li> the destination database was opened read-only, or
       
  6152 ** <li> the destination database is using write-ahead-log journaling
       
  6153 ** and the destination and source page sizes differ, or
       
  6154 ** <li> the destination database is an in-memory database and the
       
  6155 ** destination and source page sizes differ.
       
  6156 ** </ol>)^
       
  6157 **
       
  6158 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
       
  6159 ** the [sqlite3_busy_handler | busy-handler function]
       
  6160 ** is invoked (if one is specified). ^If the 
       
  6161 ** busy-handler returns non-zero before the lock is available, then 
       
  6162 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
       
  6163 ** sqlite3_backup_step() can be retried later. ^If the source
       
  6164 ** [database connection]
       
  6165 ** is being used to write to the source database when sqlite3_backup_step()
       
  6166 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
       
  6167 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
       
  6168 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
       
  6169 ** [SQLITE_READONLY] is returned, then 
       
  6170 ** there is no point in retrying the call to sqlite3_backup_step(). These 
       
  6171 ** errors are considered fatal.)^  The application must accept 
       
  6172 ** that the backup operation has failed and pass the backup operation handle 
       
  6173 ** to the sqlite3_backup_finish() to release associated resources.
       
  6174 **
       
  6175 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
       
  6176 ** on the destination file. ^The exclusive lock is not released until either 
       
  6177 ** sqlite3_backup_finish() is called or the backup operation is complete 
       
  6178 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
       
  6179 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
       
  6180 ** lasts for the duration of the sqlite3_backup_step() call.
       
  6181 ** ^Because the source database is not locked between calls to
       
  6182 ** sqlite3_backup_step(), the source database may be modified mid-way
       
  6183 ** through the backup process.  ^If the source database is modified by an
       
  6184 ** external process or via a database connection other than the one being
       
  6185 ** used by the backup operation, then the backup will be automatically
       
  6186 ** restarted by the next call to sqlite3_backup_step(). ^If the source 
       
  6187 ** database is modified by the using the same database connection as is used
       
  6188 ** by the backup operation, then the backup database is automatically
       
  6189 ** updated at the same time.
       
  6190 **
       
  6191 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
       
  6192 **
       
  6193 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
       
  6194 ** application wishes to abandon the backup operation, the application
       
  6195 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
       
  6196 ** ^The sqlite3_backup_finish() interfaces releases all
       
  6197 ** resources associated with the [sqlite3_backup] object. 
       
  6198 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
       
  6199 ** active write-transaction on the destination database is rolled back.
       
  6200 ** The [sqlite3_backup] object is invalid
       
  6201 ** and may not be used following a call to sqlite3_backup_finish().
       
  6202 **
       
  6203 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
       
  6204 ** sqlite3_backup_step() errors occurred, regardless or whether or not
       
  6205 ** sqlite3_backup_step() completed.
       
  6206 ** ^If an out-of-memory condition or IO error occurred during any prior
       
  6207 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
       
  6208 ** sqlite3_backup_finish() returns the corresponding [error code].
       
  6209 **
       
  6210 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
       
  6211 ** is not a permanent error and does not affect the return value of
       
  6212 ** sqlite3_backup_finish().
       
  6213 **
       
  6214 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
       
  6215 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
       
  6216 **
       
  6217 ** ^Each call to sqlite3_backup_step() sets two values inside
       
  6218 ** the [sqlite3_backup] object: the number of pages still to be backed
       
  6219 ** up and the total number of pages in the source database file.
       
  6220 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
       
  6221 ** retrieve these two values, respectively.
       
  6222 **
       
  6223 ** ^The values returned by these functions are only updated by
       
  6224 ** sqlite3_backup_step(). ^If the source database is modified during a backup
       
  6225 ** operation, then the values are not updated to account for any extra
       
  6226 ** pages that need to be updated or the size of the source database file
       
  6227 ** changing.
       
  6228 **
       
  6229 ** <b>Concurrent Usage of Database Handles</b>
       
  6230 **
       
  6231 ** ^The source [database connection] may be used by the application for other
       
  6232 ** purposes while a backup operation is underway or being initialized.
       
  6233 ** ^If SQLite is compiled and configured to support threadsafe database
       
  6234 ** connections, then the source database connection may be used concurrently
       
  6235 ** from within other threads.
       
  6236 **
       
  6237 ** However, the application must guarantee that the destination 
       
  6238 ** [database connection] is not passed to any other API (by any thread) after 
       
  6239 ** sqlite3_backup_init() is called and before the corresponding call to
       
  6240 ** sqlite3_backup_finish().  SQLite does not currently check to see
       
  6241 ** if the application incorrectly accesses the destination [database connection]
       
  6242 ** and so no error code is reported, but the operations may malfunction
       
  6243 ** nevertheless.  Use of the destination database connection while a
       
  6244 ** backup is in progress might also also cause a mutex deadlock.
       
  6245 **
       
  6246 ** If running in [shared cache mode], the application must
       
  6247 ** guarantee that the shared cache used by the destination database
       
  6248 ** is not accessed while the backup is running. In practice this means
       
  6249 ** that the application must guarantee that the disk file being 
       
  6250 ** backed up to is not accessed by any connection within the process,
       
  6251 ** not just the specific connection that was passed to sqlite3_backup_init().
       
  6252 **
       
  6253 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
       
  6254 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
       
  6255 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
       
  6256 ** APIs are not strictly speaking threadsafe. If they are invoked at the
       
  6257 ** same time as another thread is invoking sqlite3_backup_step() it is
       
  6258 ** possible that they return invalid values.
       
  6259 */
       
  6260 SQLITE_API sqlite3_backup *sqlite3_backup_init(
       
  6261   sqlite3 *pDest,                        /* Destination database handle */
       
  6262   const char *zDestName,                 /* Destination database name */
       
  6263   sqlite3 *pSource,                      /* Source database handle */
       
  6264   const char *zSourceName                /* Source database name */
       
  6265 );
       
  6266 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
       
  6267 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
       
  6268 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
       
  6269 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
       
  6270 
       
  6271 /*
       
  6272 ** CAPI3REF: Unlock Notification
       
  6273 **
       
  6274 ** ^When running in shared-cache mode, a database operation may fail with
       
  6275 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
       
  6276 ** individual tables within the shared-cache cannot be obtained. See
       
  6277 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
       
  6278 ** ^This API may be used to register a callback that SQLite will invoke 
       
  6279 ** when the connection currently holding the required lock relinquishes it.
       
  6280 ** ^This API is only available if the library was compiled with the
       
  6281 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
       
  6282 **
       
  6283 ** See Also: [Using the SQLite Unlock Notification Feature].
       
  6284 **
       
  6285 ** ^Shared-cache locks are released when a database connection concludes
       
  6286 ** its current transaction, either by committing it or rolling it back. 
       
  6287 **
       
  6288 ** ^When a connection (known as the blocked connection) fails to obtain a
       
  6289 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
       
  6290 ** identity of the database connection (the blocking connection) that
       
  6291 ** has locked the required resource is stored internally. ^After an 
       
  6292 ** application receives an SQLITE_LOCKED error, it may call the
       
  6293 ** sqlite3_unlock_notify() method with the blocked connection handle as 
       
  6294 ** the first argument to register for a callback that will be invoked
       
  6295 ** when the blocking connections current transaction is concluded. ^The
       
  6296 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
       
  6297 ** call that concludes the blocking connections transaction.
       
  6298 **
       
  6299 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
       
  6300 ** there is a chance that the blocking connection will have already
       
  6301 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
       
  6302 ** If this happens, then the specified callback is invoked immediately,
       
  6303 ** from within the call to sqlite3_unlock_notify().)^
       
  6304 **
       
  6305 ** ^If the blocked connection is attempting to obtain a write-lock on a
       
  6306 ** shared-cache table, and more than one other connection currently holds
       
  6307 ** a read-lock on the same table, then SQLite arbitrarily selects one of 
       
  6308 ** the other connections to use as the blocking connection.
       
  6309 **
       
  6310 ** ^(There may be at most one unlock-notify callback registered by a 
       
  6311 ** blocked connection. If sqlite3_unlock_notify() is called when the
       
  6312 ** blocked connection already has a registered unlock-notify callback,
       
  6313 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
       
  6314 ** called with a NULL pointer as its second argument, then any existing
       
  6315 ** unlock-notify callback is canceled. ^The blocked connections 
       
  6316 ** unlock-notify callback may also be canceled by closing the blocked
       
  6317 ** connection using [sqlite3_close()].
       
  6318 **
       
  6319 ** The unlock-notify callback is not reentrant. If an application invokes
       
  6320 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
       
  6321 ** crash or deadlock may be the result.
       
  6322 **
       
  6323 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
       
  6324 ** returns SQLITE_OK.
       
  6325 **
       
  6326 ** <b>Callback Invocation Details</b>
       
  6327 **
       
  6328 ** When an unlock-notify callback is registered, the application provides a 
       
  6329 ** single void* pointer that is passed to the callback when it is invoked.
       
  6330 ** However, the signature of the callback function allows SQLite to pass
       
  6331 ** it an array of void* context pointers. The first argument passed to
       
  6332 ** an unlock-notify callback is a pointer to an array of void* pointers,
       
  6333 ** and the second is the number of entries in the array.
       
  6334 **
       
  6335 ** When a blocking connections transaction is concluded, there may be
       
  6336 ** more than one blocked connection that has registered for an unlock-notify
       
  6337 ** callback. ^If two or more such blocked connections have specified the
       
  6338 ** same callback function, then instead of invoking the callback function
       
  6339 ** multiple times, it is invoked once with the set of void* context pointers
       
  6340 ** specified by the blocked connections bundled together into an array.
       
  6341 ** This gives the application an opportunity to prioritize any actions 
       
  6342 ** related to the set of unblocked database connections.
       
  6343 **
       
  6344 ** <b>Deadlock Detection</b>
       
  6345 **
       
  6346 ** Assuming that after registering for an unlock-notify callback a 
       
  6347 ** database waits for the callback to be issued before taking any further
       
  6348 ** action (a reasonable assumption), then using this API may cause the
       
  6349 ** application to deadlock. For example, if connection X is waiting for
       
  6350 ** connection Y's transaction to be concluded, and similarly connection
       
  6351 ** Y is waiting on connection X's transaction, then neither connection
       
  6352 ** will proceed and the system may remain deadlocked indefinitely.
       
  6353 **
       
  6354 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
       
  6355 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
       
  6356 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
       
  6357 ** unlock-notify callback is registered. The system is said to be in
       
  6358 ** a deadlocked state if connection A has registered for an unlock-notify
       
  6359 ** callback on the conclusion of connection B's transaction, and connection
       
  6360 ** B has itself registered for an unlock-notify callback when connection
       
  6361 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
       
  6362 ** the system is also considered to be deadlocked if connection B has
       
  6363 ** registered for an unlock-notify callback on the conclusion of connection
       
  6364 ** C's transaction, where connection C is waiting on connection A. ^Any
       
  6365 ** number of levels of indirection are allowed.
       
  6366 **
       
  6367 ** <b>The "DROP TABLE" Exception</b>
       
  6368 **
       
  6369 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
       
  6370 ** always appropriate to call sqlite3_unlock_notify(). There is however,
       
  6371 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
       
  6372 ** SQLite checks if there are any currently executing SELECT statements
       
  6373 ** that belong to the same connection. If there are, SQLITE_LOCKED is
       
  6374 ** returned. In this case there is no "blocking connection", so invoking
       
  6375 ** sqlite3_unlock_notify() results in the unlock-notify callback being
       
  6376 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
       
  6377 ** or "DROP INDEX" query, an infinite loop might be the result.
       
  6378 **
       
  6379 ** One way around this problem is to check the extended error code returned
       
  6380 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
       
  6381 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
       
  6382 ** the special "DROP TABLE/INDEX" case, the extended error code is just 
       
  6383 ** SQLITE_LOCKED.)^
       
  6384 */
       
  6385 SQLITE_API int sqlite3_unlock_notify(
       
  6386   sqlite3 *pBlocked,                          /* Waiting connection */
       
  6387   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
       
  6388   void *pNotifyArg                            /* Argument to pass to xNotify */
       
  6389 );
       
  6390 
       
  6391 
       
  6392 /*
       
  6393 ** CAPI3REF: String Comparison
       
  6394 **
       
  6395 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to
       
  6396 ** compare the contents of two buffers containing UTF-8 strings in a
       
  6397 ** case-independent fashion, using the same definition of case independence 
       
  6398 ** that SQLite uses internally when comparing identifiers.
       
  6399 */
       
  6400 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
       
  6401 
       
  6402 /*
       
  6403 ** CAPI3REF: Error Logging Interface
       
  6404 **
       
  6405 ** ^The [sqlite3_log()] interface writes a message into the error log
       
  6406 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
       
  6407 ** ^If logging is enabled, the zFormat string and subsequent arguments are
       
  6408 ** used with [sqlite3_snprintf()] to generate the final output string.
       
  6409 **
       
  6410 ** The sqlite3_log() interface is intended for use by extensions such as
       
  6411 ** virtual tables, collating functions, and SQL functions.  While there is
       
  6412 ** nothing to prevent an application from calling sqlite3_log(), doing so
       
  6413 ** is considered bad form.
       
  6414 **
       
  6415 ** The zFormat string must not be NULL.
       
  6416 **
       
  6417 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
       
  6418 ** will not use dynamically allocated memory.  The log message is stored in
       
  6419 ** a fixed-length buffer on the stack.  If the log message is longer than
       
  6420 ** a few hundred characters, it will be truncated to the length of the
       
  6421 ** buffer.
       
  6422 */
       
  6423 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
       
  6424 
       
  6425 /*
       
  6426 ** CAPI3REF: Write-Ahead Log Commit Hook
       
  6427 **
       
  6428 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
       
  6429 ** will be invoked each time a database connection commits data to a
       
  6430 ** [write-ahead log] (i.e. whenever a transaction is committed in
       
  6431 ** [journal_mode | journal_mode=WAL mode]). 
       
  6432 **
       
  6433 ** ^The callback is invoked by SQLite after the commit has taken place and 
       
  6434 ** the associated write-lock on the database released, so the implementation 
       
  6435 ** may read, write or [checkpoint] the database as required.
       
  6436 **
       
  6437 ** ^The first parameter passed to the callback function when it is invoked
       
  6438 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
       
  6439 ** registering the callback. ^The second is a copy of the database handle.
       
  6440 ** ^The third parameter is the name of the database that was written to -
       
  6441 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
       
  6442 ** is the number of pages currently in the write-ahead log file,
       
  6443 ** including those that were just committed.
       
  6444 **
       
  6445 ** The callback function should normally return [SQLITE_OK].  ^If an error
       
  6446 ** code is returned, that error will propagate back up through the
       
  6447 ** SQLite code base to cause the statement that provoked the callback
       
  6448 ** to report an error, though the commit will have still occurred. If the
       
  6449 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
       
  6450 ** that does not correspond to any valid SQLite error code, the results
       
  6451 ** are undefined.
       
  6452 **
       
  6453 ** A single database handle may have at most a single write-ahead log callback 
       
  6454 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
       
  6455 ** previously registered write-ahead log callback. ^Note that the
       
  6456 ** [sqlite3_wal_autocheckpoint()] interface and the
       
  6457 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
       
  6458 ** those overwrite any prior [sqlite3_wal_hook()] settings.
       
  6459 */
       
  6460 SQLITE_API void *sqlite3_wal_hook(
       
  6461   sqlite3*, 
       
  6462   int(*)(void *,sqlite3*,const char*,int),
       
  6463   void*
       
  6464 );
       
  6465 
       
  6466 /*
       
  6467 ** CAPI3REF: Configure an auto-checkpoint
       
  6468 **
       
  6469 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
       
  6470 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
       
  6471 ** to automatically [checkpoint]
       
  6472 ** after committing a transaction if there are N or
       
  6473 ** more frames in the [write-ahead log] file.  ^Passing zero or 
       
  6474 ** a negative value as the nFrame parameter disables automatic
       
  6475 ** checkpoints entirely.
       
  6476 **
       
  6477 ** ^The callback registered by this function replaces any existing callback
       
  6478 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
       
  6479 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
       
  6480 ** configured by this function.
       
  6481 **
       
  6482 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
       
  6483 ** from SQL.
       
  6484 **
       
  6485 ** ^Every new [database connection] defaults to having the auto-checkpoint
       
  6486 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
       
  6487 ** pages.  The use of this interface
       
  6488 ** is only necessary if the default setting is found to be suboptimal
       
  6489 ** for a particular application.
       
  6490 */
       
  6491 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
       
  6492 
       
  6493 /*
       
  6494 ** CAPI3REF: Checkpoint a database
       
  6495 **
       
  6496 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
       
  6497 ** on [database connection] D to be [checkpointed].  ^If X is NULL or an
       
  6498 ** empty string, then a checkpoint is run on all databases of
       
  6499 ** connection D.  ^If the database connection D is not in
       
  6500 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
       
  6501 **
       
  6502 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
       
  6503 ** from SQL.  ^The [sqlite3_wal_autocheckpoint()] interface and the
       
  6504 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
       
  6505 ** run whenever the WAL reaches a certain size threshold.
       
  6506 **
       
  6507 ** See also: [sqlite3_wal_checkpoint_v2()]
       
  6508 */
       
  6509 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
       
  6510 
       
  6511 /*
       
  6512 ** CAPI3REF: Checkpoint a database
       
  6513 **
       
  6514 ** Run a checkpoint operation on WAL database zDb attached to database 
       
  6515 ** handle db. The specific operation is determined by the value of the 
       
  6516 ** eMode parameter:
       
  6517 **
       
  6518 ** <dl>
       
  6519 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
       
  6520 **   Checkpoint as many frames as possible without waiting for any database 
       
  6521 **   readers or writers to finish. Sync the db file if all frames in the log
       
  6522 **   are checkpointed. This mode is the same as calling 
       
  6523 **   sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
       
  6524 **
       
  6525 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
       
  6526 **   This mode blocks (calls the busy-handler callback) until there is no
       
  6527 **   database writer and all readers are reading from the most recent database
       
  6528 **   snapshot. It then checkpoints all frames in the log file and syncs the
       
  6529 **   database file. This call blocks database writers while it is running,
       
  6530 **   but not database readers.
       
  6531 **
       
  6532 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
       
  6533 **   This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 
       
  6534 **   checkpointing the log file it blocks (calls the busy-handler callback)
       
  6535 **   until all readers are reading from the database file only. This ensures 
       
  6536 **   that the next client to write to the database file restarts the log file 
       
  6537 **   from the beginning. This call blocks database writers while it is running,
       
  6538 **   but not database readers.
       
  6539 ** </dl>
       
  6540 **
       
  6541 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
       
  6542 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
       
  6543 ** the total number of checkpointed frames (including any that were already
       
  6544 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
       
  6545 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
       
  6546 ** If no values are available because of an error, they are both set to -1
       
  6547 ** before returning to communicate this to the caller.
       
  6548 **
       
  6549 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
       
  6550 ** any other process is running a checkpoint operation at the same time, the 
       
  6551 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 
       
  6552 ** busy-handler configured, it will not be invoked in this case.
       
  6553 **
       
  6554 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 
       
  6555 ** "writer" lock on the database file. If the writer lock cannot be obtained
       
  6556 ** immediately, and a busy-handler is configured, it is invoked and the writer
       
  6557 ** lock retried until either the busy-handler returns 0 or the lock is
       
  6558 ** successfully obtained. The busy-handler is also invoked while waiting for
       
  6559 ** database readers as described above. If the busy-handler returns 0 before
       
  6560 ** the writer lock is obtained or while waiting for database readers, the
       
  6561 ** checkpoint operation proceeds from that point in the same way as 
       
  6562 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 
       
  6563 ** without blocking any further. SQLITE_BUSY is returned in this case.
       
  6564 **
       
  6565 ** If parameter zDb is NULL or points to a zero length string, then the
       
  6566 ** specified operation is attempted on all WAL databases. In this case the
       
  6567 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 
       
  6568 ** an SQLITE_BUSY error is encountered when processing one or more of the 
       
  6569 ** attached WAL databases, the operation is still attempted on any remaining 
       
  6570 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 
       
  6571 ** error occurs while processing an attached database, processing is abandoned 
       
  6572 ** and the error code returned to the caller immediately. If no error 
       
  6573 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 
       
  6574 ** databases, SQLITE_OK is returned.
       
  6575 **
       
  6576 ** If database zDb is the name of an attached database that is not in WAL
       
  6577 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
       
  6578 ** zDb is not NULL (or a zero length string) and is not the name of any
       
  6579 ** attached database, SQLITE_ERROR is returned to the caller.
       
  6580 */
       
  6581 SQLITE_API int sqlite3_wal_checkpoint_v2(
       
  6582   sqlite3 *db,                    /* Database handle */
       
  6583   const char *zDb,                /* Name of attached database (or NULL) */
       
  6584   int eMode,                      /* SQLITE_CHECKPOINT_* value */
       
  6585   int *pnLog,                     /* OUT: Size of WAL log in frames */
       
  6586   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
       
  6587 );
       
  6588 
       
  6589 /*
       
  6590 ** CAPI3REF: Checkpoint operation parameters
       
  6591 **
       
  6592 ** These constants can be used as the 3rd parameter to
       
  6593 ** [sqlite3_wal_checkpoint_v2()].  See the [sqlite3_wal_checkpoint_v2()]
       
  6594 ** documentation for additional information about the meaning and use of
       
  6595 ** each of these values.
       
  6596 */
       
  6597 #define SQLITE_CHECKPOINT_PASSIVE 0
       
  6598 #define SQLITE_CHECKPOINT_FULL    1
       
  6599 #define SQLITE_CHECKPOINT_RESTART 2
       
  6600 
       
  6601 /*
       
  6602 ** CAPI3REF: Virtual Table Interface Configuration
       
  6603 **
       
  6604 ** This function may be called by either the [xConnect] or [xCreate] method
       
  6605 ** of a [virtual table] implementation to configure
       
  6606 ** various facets of the virtual table interface.
       
  6607 **
       
  6608 ** If this interface is invoked outside the context of an xConnect or
       
  6609 ** xCreate virtual table method then the behavior is undefined.
       
  6610 **
       
  6611 ** At present, there is only one option that may be configured using
       
  6612 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
       
  6613 ** may be added in the future.
       
  6614 */
       
  6615 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
       
  6616 
       
  6617 /*
       
  6618 ** CAPI3REF: Virtual Table Configuration Options
       
  6619 **
       
  6620 ** These macros define the various options to the
       
  6621 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
       
  6622 ** can use to customize and optimize their behavior.
       
  6623 **
       
  6624 ** <dl>
       
  6625 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
       
  6626 ** <dd>Calls of the form
       
  6627 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
       
  6628 ** where X is an integer.  If X is zero, then the [virtual table] whose
       
  6629 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
       
  6630 ** support constraints.  In this configuration (which is the default) if
       
  6631 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
       
  6632 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
       
  6633 ** specified as part of the users SQL statement, regardless of the actual
       
  6634 ** ON CONFLICT mode specified.
       
  6635 **
       
  6636 ** If X is non-zero, then the virtual table implementation guarantees
       
  6637 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
       
  6638 ** any modifications to internal or persistent data structures have been made.
       
  6639 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 
       
  6640 ** is able to roll back a statement or database transaction, and abandon
       
  6641 ** or continue processing the current SQL statement as appropriate. 
       
  6642 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
       
  6643 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
       
  6644 ** had been ABORT.
       
  6645 **
       
  6646 ** Virtual table implementations that are required to handle OR REPLACE
       
  6647 ** must do so within the [xUpdate] method. If a call to the 
       
  6648 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 
       
  6649 ** CONFLICT policy is REPLACE, the virtual table implementation should 
       
  6650 ** silently replace the appropriate rows within the xUpdate callback and
       
  6651 ** return SQLITE_OK. Or, if this is not possible, it may return
       
  6652 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 
       
  6653 ** constraint handling.
       
  6654 ** </dl>
       
  6655 */
       
  6656 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
       
  6657 
       
  6658 /*
       
  6659 ** CAPI3REF: Determine The Virtual Table Conflict Policy
       
  6660 **
       
  6661 ** This function may only be called from within a call to the [xUpdate] method
       
  6662 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
       
  6663 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
       
  6664 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
       
  6665 ** of the SQL statement that triggered the call to the [xUpdate] method of the
       
  6666 ** [virtual table].
       
  6667 */
       
  6668 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
       
  6669 
       
  6670 /*
       
  6671 ** CAPI3REF: Conflict resolution modes
       
  6672 **
       
  6673 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
       
  6674 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
       
  6675 ** is for the SQL statement being evaluated.
       
  6676 **
       
  6677 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
       
  6678 ** return value from the [sqlite3_set_authorizer()] callback and that
       
  6679 ** [SQLITE_ABORT] is also a [result code].
       
  6680 */
       
  6681 #define SQLITE_ROLLBACK 1
       
  6682 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
       
  6683 #define SQLITE_FAIL     3
       
  6684 /* #define SQLITE_ABORT 4  // Also an error code */
       
  6685 #define SQLITE_REPLACE  5
       
  6686 
       
  6687 
       
  6688 
       
  6689 /*
       
  6690 ** Undo the hack that converts floating point types to integer for
       
  6691 ** builds on processors without floating point support.
       
  6692 */
       
  6693 #ifdef SQLITE_OMIT_FLOATING_POINT
       
  6694 # undef double
       
  6695 #endif
       
  6696 
       
  6697 #ifdef __cplusplus
       
  6698 }  /* End of the 'extern "C"' block */
       
  6699 #endif
       
  6700 #endif
       
  6701 
       
  6702 /*
       
  6703 ** 2010 August 30
       
  6704 **
       
  6705 ** The author disclaims copyright to this source code.  In place of
       
  6706 ** a legal notice, here is a blessing:
       
  6707 **
       
  6708 **    May you do good and not evil.
       
  6709 **    May you find forgiveness for yourself and forgive others.
       
  6710 **    May you share freely, never taking more than you give.
       
  6711 **
       
  6712 *************************************************************************
       
  6713 */
       
  6714 
       
  6715 #ifndef _SQLITE3RTREE_H_
       
  6716 #define _SQLITE3RTREE_H_
       
  6717 
       
  6718 
       
  6719 #ifdef __cplusplus
       
  6720 extern "C" {
       
  6721 #endif
       
  6722 
       
  6723 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
       
  6724 
       
  6725 /*
       
  6726 ** Register a geometry callback named zGeom that can be used as part of an
       
  6727 ** R-Tree geometry query as follows:
       
  6728 **
       
  6729 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
       
  6730 */
       
  6731 SQLITE_API int sqlite3_rtree_geometry_callback(
       
  6732   sqlite3 *db,
       
  6733   const char *zGeom,
       
  6734   int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes),
       
  6735   void *pContext
       
  6736 );
       
  6737 
       
  6738 
       
  6739 /*
       
  6740 ** A pointer to a structure of the following type is passed as the first
       
  6741 ** argument to callbacks registered using rtree_geometry_callback().
       
  6742 */
       
  6743 struct sqlite3_rtree_geometry {
       
  6744   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
       
  6745   int nParam;                     /* Size of array aParam[] */
       
  6746   double *aParam;                 /* Parameters passed to SQL geom function */
       
  6747   void *pUser;                    /* Callback implementation user data */
       
  6748   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
       
  6749 };
       
  6750 
       
  6751 
       
  6752 #ifdef __cplusplus
       
  6753 }  /* end of the 'extern "C"' block */
       
  6754 #endif
       
  6755 
       
  6756 #endif  /* ifndef _SQLITE3RTREE_H_ */
       
  6757