69 		# No-op the stupid squashing of output

    69 

    70 		# Create a new Availability instance.

    71 		#

    72 		# Valid keys for the options hash include:

    73 		# * <tt>:loaded_libs</tt> -- libraries to load by default

    74 		# * <tt>:library_paths</tt> -- libraries paths to include by default

    75 		# * <tt>:headers</tt> -- headers to load by default

    76 		# * <tt>:compiler</tt> -- which compiler to use when determining availability

    77 		# * <tt>:includes</tt> -- directories that should be searched for include files

    78 		def initialize(options = {})      

    79 			@loaded_libs = options[:loaded_libs] || []

    80 			@loaded_libs.flatten!

    81 

    82 			@library_paths = [(options[:library_paths] || [])].flatten

    83 			# Not sure what COMMON_HEADERS looks like when populated

    84 			@headers = options[:headers] || [] # Config::CONFIG["COMMON_HEADERS"]

    85 			@compiler = options[:compiler] || Config::CONFIG["CC"]

    86 			@includes = [(options[:includes] || DEFAULT_INCLUDES)].flatten

    87 			@logger = Logger.new('mkrf.log')

    88 			@defines = []

    89 		end

    90 

    91 

    92 		def can_link?( function_body )

    93 			silence_command_line do

    94 				create_source(function_body)

    95 				cmd = link_command()

    96 				@logger.debug "Running link command: #{cmd}"

    97 				system( cmd )

    98 			end

    99 		ensure

   100 			FileUtils.rm_f TEMP_SOURCE_FILE

   101 			FileUtils.rm_f TEMP_EXECUTABLE

   102 		end

   103 

   104 

   105 		# Add the LIBRUBYARG_SHARED setting to the library paths for non-windows boxen. This is

   106 		# necessary if Ruby is installed in a directory that isn't in the default library

   107 		# search path (e.g., on FreeBSD where Ruby is /usr/local/bin/ruby).

   108 		def library_paths_compile_string

   109 			if RUBY_PLATFORM =~ /mswin/

   110 				@library_paths.collect {|l| "/libpath:#{l}"}.join(' ')

   111 			else

   112 				Config::CONFIG['LIBRUBYARG_SHARED'] + @library_paths.collect {|l| "-L#{l}"}.join(' ')

   113 			end

   114 		end

   115 

   116 

   117 		# Separate includes with a newline instead of a literal '\n'

   118 		def header_include_string

   119 			@headers.collect {|header| "#include <#{header}>"}.join( "\n" )

   120 		end

   121 

   122 

   123 		# Log the created source to the logfile

   124 		def create_source( src )

   125 			@logger.debug "Creating source file:\n#{src}"

   126 			File.open( TEMP_SOURCE_FILE, "w+" ) do |f|

   127 				f.write( src )

   128 			end

   129 		end

   130 

   131 		# Prepend the LIBS string directly to the @loaded_libs, as not all arguments in

   132 		# it 

   133 		def library_compile_string

   134 			added_libs = nil

   135 			if RUBY_PLATFORM =~ /mswin/

   136 				added_libs = @loaded_libs.join(' ')

   137 			else

   138 				added_libs = @loaded_libs.collect {|l| "-l#{l}"}.join(' ')

   139 			end

   140 			

   141 			return Config::CONFIG["LIBS"] + ' ' + added_libs

   142 		end

   143 

   144 

   145 		# Redirect to the mkrf log instead of /dev/null