Add a minimal C program for testing misc.

FossilOrigin-Name: d5691ca991f0fe53f7ae1ce759288770547132879ccc75ea16a0a350737272d2

experiments/minimal.c

@@ -0,0 +1,51 @@
+
+/*
+* clang -L/usr/local/lib -I/usr/local/include -lmdbx minimal.c -o minimal-tset
+*/
+
+#include "mdbx.h"
+#include "assert.h"
+
+
+int
+main()
+{
+	MDBX_env *env;
+	MDBX_txn *txn;
+	MDBX_dbi dbi;
+	int rc;
+
+	rc = mdbx_env_create( &env );
+	assert( rc == MDBX_SUCCESS );
+
+	rc = mdbx_env_open( env, "./testdb", MDBX_ENV_DEFAULTS, 0644 );
+	assert( rc == MDBX_SUCCESS );
+
+	/*
+	 * Using a read/write transaction handle for mdbx_dbi_open()
+	 * works in all cases.
+	 *
+	 */
+	// rc = mdbx_txn_begin( env, NULL, MDBX_TXN_READWRITE, &txn );
+	
+	/*
+	 * Using a readonly transaction handle seemingly fails for
+	 * use with mdbx_dbi_open().
+	 *
+	 */
+	rc = mdbx_txn_begin( env, NULL, MDBX_TXN_RDONLY, &txn );
+	assert( rc == MDBX_SUCCESS );
+
+	rc = mdbx_dbi_open( txn, NULL, MDBX_DB_DEFAULTS|MDBX_CREATE, &dbi );
+	assert( rc == MDBX_SUCCESS );
+
+	mdbx_txn_abort( txn );
+
+
+
+	mdbx_dbi_close( env, dbi );
+	mdbx_env_close( env );
+	mdbx_txn_abort( txn );
+
+	return( 0 );
+}