Provided by: libconfig-autoconf-perl_0.311-1_all bug

NAME

       Config::AutoConf - A module to implement some of AutoConf macros in pure perl.

ABSTRACT

       With this module I pretend to simulate some of the tasks AutoConf macros do. To detect a
       command, to detect a library, etc.

SYNOPSIS

           use Config::AutoConf;

           Config::AutoConf->check_prog("agrep");
           my $grep = Config::AutoConf->check_progs("agrep", "egrep", "grep");

           Config::AutoConf->check_header("ncurses.h");
           my $curses = Config::AutoConf->check_headers("ncurses.h","curses.h");

           Config::AutoConf->check_prog_awk;
           Config::AutoConf->check_prog_egrep;

           Config::AutoConf->check_cc();

           Config::AutoConf->check_lib("ncurses", "tgoto");

           Config::AutoConf->check_file("/etc/passwd"); # -f && -r

DESCRIPTION

       Config::AutoConf is intended to provide the same opportunities to Perl developers as GNU
       Autoconf <http://www.gnu.org/software/autoconf/> does for Shell developers.

       As Perl is the second most deployed language (mind: every Unix comes with Perl, several
       mini-computers have Perl and even lot's of Windows machines run Perl software - which
       requires deployed Perl there, too), this gives wider support than Shell based probes.

       The API is leaned against GNU Autoconf, but we try to make the API (especially optional
       arguments) more Perl'ish than m4 abilities allow to the original.

FUNCTIONS

   new
       This function instantiates a new instance of Config::AutoConf, eg. to configure child
       components. The constructor adds also values set via environment variable
       "PERL5_AUTOCONF_OPTS".

   check_file
       This function checks if a file exists in the system and is readable by the user. Returns a
       boolean. You can use '-f $file && -r $file' so you don't need to use a function call.

   check_files
       This function checks if a set of files exist in the system and are readable by the user.
       Returns a boolean.

   check_prog( $prog, \@dirlist?, \%options? )
       This function checks for a program with the supplied name. In success returns the full
       path for the executable;

       An optional array reference containing a list of directories to be searched instead of
       $PATH is gracefully honored.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.

   check_progs(progs, [dirlist])
       This function takes a list of program names. Returns the full path for the first found on
       the system. Returns undef if none was found.

       An optional array reference containing a list of directories to be searched instead of
       $PATH is gracefully honored.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively. The name of the $prog to check and the
       found full path are passed as first and second argument to the action_on_true callback.

   check_prog_yacc
       From the autoconf documentation,

         If `bison' is found, set [...] `bison -y'.
         Otherwise, if `byacc' is found, set [...] `byacc'.
         Otherwise set [...] `yacc'.  The result of this test can be influenced
         by setting the variable YACC or the cache variable ac_cv_prog_YACC.

       Returns the full path, if found.

   check_prog_awk
       From the autoconf documentation,

         Check for `gawk', `mawk', `nawk', and `awk', in that order, and
         set output [...] to the first one that is found.  It tries
         `gawk' first because that is reported to be the best implementation.
         The result can be overridden by setting the variable AWK or the
         cache variable ac_cv_prog_AWK.

       Note that it returns the full path, if found.

   check_prog_egrep
       From the autoconf documentation,

         Check for `grep -E' and `egrep', in that order, and [...] output
         [...] the first one that is found.  The result can be overridden by
         setting the EGREP variable and is cached in the ac_cv_path_EGREP
         variable.

       Note that it returns the full path, if found.

   check_prog_lex
       From the autoconf documentation,

         If flex is found, set output [...] to XflexX and [...] to -lfl, if that
         library is in a standard place. Otherwise set output [...] to XlexX and
         [...] to -ll, if found. If [...] packages [...] ship the generated
         file.yy.c alongside the source file.l, this [...] allows users without a
         lexer generator to still build the package even if the timestamp for
         file.l is inadvertently changed.

       Note that it returns the full path, if found.

       The structure $self->{lex} is set with attributes

         prog => $LEX
         lib => $LEXLIB
         root => $lex_root

   check_prog_sed
       From the autoconf documentation,

         Set output variable [...] to a Sed implementation that conforms to Posix
         and does not have arbitrary length limits. Report an error if no
         acceptable Sed is found. See Limitations of Usual Tools, for more
         information about portability problems with Sed.

         The result of this test can be overridden by setting the SED variable and
         is cached in the ac_cv_path_SED variable.

       Note that it returns the full path, if found.

   check_prog_pkg_config
       Checks for "pkg-config" program. No additional tests are made for it ...

   check_prog_cc
       Determine a C compiler to use. Currently the probe is delegated to ExtUtils::CBuilder.

   check_cc
       (Deprecated) Old name of "check_prog_cc".

   check_valid_compiler
       This function checks for a valid compiler for the currently active language.  At the very
       moment only "C" is understood (corresponding to your compiler default options, e.g.
       -std=gnu89).

   check_valid_compilers(;\@)
       Checks for valid compilers for each given language. When unspecified defaults to "[ "C"
       ]".

   msg_checking
       Prints "Checking @_ ..."

   msg_result
       Prints result \n

   msg_notice
       Prints "configure: " @_ to stdout

   msg_warn
       Prints "configure: " @_ to stderr

   msg_error
       Prints "configure: " @_ to stderr and exits with exit code 0 (tells toolchain to stop here
       and report unsupported environment)

   msg_failure
       Prints "configure: " @_ to stderr and exits with exit code 0 (tells toolchain to stop here
       and report unsupported environment). Additional details are provides in config.log
       (probably more information in a later stage).

   define_var( $name, $value [, $comment ] )
       Defines a check variable for later use in further checks or code to compile.  Returns the
       value assigned value

   write_config_h( [$target] )
       Writes the defined constants into given target:

         Config::AutoConf->write_config_h( "config.h" );

   push_lang(lang [, implementor ])
       Puts the current used language on the stack and uses specified language for subsequent
       operations until ending pop_lang call.

   pop_lang([ lang ])
       Pops the currently used language from the stack and restores previously used language. If
       lang specified, it's asserted that the current used language equals to specified language
       (helps finding control flow bugs).

   lang_call( [prologue], function )
       Builds program which simply calls given function.  When given, prologue is prepended
       otherwise, the default includes are used.

   lang_build_program( prologue, body )
       Builds program for current chosen language. If no prologue is given (undef), the default
       headers are used. If body is missing, default body is used.

       Typical call of

         Config::AutoConf->lang_build_program( "const char hw[] = \"Hello, World\\n\";",
                                               "fputs (hw, stdout);" )

       will create

         const char hw[] = "Hello, World\n";

         /* Override any gcc2 internal prototype to avoid an error.  */
         #ifdef __cplusplus
         extern "C" {
         #endif

         int
         main (int argc, char **argv)
         {
           (void)argc;
           (void)argv;
           fputs (hw, stdout);;
           return 0;
         }

         #ifdef __cplusplus
         }
         #endif

   lang_build_bool_test (prologue, test, [@decls])
       Builds a static test which will fail to compile when test evaluates to false. If @decls is
       given, it's prepended before the test code at the variable definition place.

   push_includes
       Adds given list of directories to preprocessor/compiler invocation. This is not proved to
       allow adding directories which might be created during the build.

   push_preprocess_flags
       Adds given flags to the parameter list for preprocessor invocation.

   push_compiler_flags
       Adds given flags to the parameter list for compiler invocation.

   push_libraries
       Adds given list of libraries to the parameter list for linker invocation.

   push_library_paths
       Adds given list of library paths to the parameter list for linker invocation.

   push_link_flags
       Adds given flags to the parameter list for linker invocation.

   compile_if_else( $src, \%options? )
       This function tries to compile specified code and returns a boolean value containing check
       success state.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.

   link_if_else( $src, \%options? )
       This function tries to compile and link specified code and returns a boolean value
       containing check success state.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.

   check_cached( $cache-key, $check-title, \&check-call, \%options? )
       Retrieves the result of a previous "check_cached" invocation from "cache-key", or (when
       called for the first time) populates the cache by invoking "\&check_call".

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed on every call to check_cached (not just the first cache-
       populating invocation), respectively.

   cache_val
       This function returns the value of a previously check_cached call.

   check_decl( $symbol, \%options? )
       This method actually tests whether symbol is defined as a macro or can be used as an
       r-value, not whether it is really declared, because it is much safer to avoid introducing
       extra declarations when they are not needed.  In order to facilitate use of C++ and
       overloaded function declarations, it is possible to specify function argument types in
       parentheses for types which can be zero-initialized:

         Config::AutoConf->check_decl("basename(char *)")

       This method caches its result in the "ac_cv_decl_<set lang>"_symbol variable.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.

   check_decls( symbols, \%options? )
       For each of the symbols (with optional function argument types for C++ overloads), run
       check_decl.

       Contrary to GNU autoconf, this method does not declare HAVE_DECL_symbol macros for the
       resulting "confdefs.h", because it differs as "check_decl" between compiling languages.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.  Given callbacks for action_on_symbol_true or
       action_on_symbol_false are called for each symbol checked using "check_decl" receiving the
       symbol as first argument.

   check_func( $function, \%options? )
       This method actually tests whether $funcion can be linked into a program trying to call
       $function.  This method caches its result in the ac_cv_func_FUNCTION variable.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  If any of action_on_cache_true,
       action_on_cache_false is defined, both callbacks are passed to "check_cached" as
       action_on_true or action_on_false to "check_cached", respectively.

       Returns: True if the function was found, false otherwise

   check_funcs( \@functions-list, $action-if-true?, $action-if-false? )
       The same as check_func, but takes a list of functions in \@functions-list to look for and
       checks for each in turn. Define HAVE_FUNCTION for each function that was found.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  If any of action_on_cache_true,
       action_on_cache_false is defined, both callbacks are passed to "check_cached" as
       action_on_true or action_on_false to "check_cached", respectively.  Given callbacks for
       action_on_function_true or action_on_function_false are called for each symbol checked
       using "check_func" receiving the symbol as first argument.

   check_type( $symbol, \%options? )
       Check whether type is defined. It may be a compiler builtin type or defined by the
       includes.  In C, type must be a type-name, so that the expression "sizeof (type)" is valid
       (but "sizeof ((type))" is not).

       If type type is defined, preprocessor macro HAVE_type (in all capitals, with "*" replaced
       by "P" and spaces and dots replaced by underscores) is defined.

       This method caches its result in the "ac_cv_type_"type variable.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.

   check_types( \@type-list, \%options? )
       For each type in @type-list, call check_type is called to check for type and return the
       accumulated result (accumulation op is binary and).

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.  Given callbacks for action_on_type_true or
       action_on_type_false are called for each symbol checked using "check_type" receiving the
       symbol as first argument.

   compute_int( $expression, @decls?, \%options )
       Returns the value of the integer expression. The value should fit in an initializer in a C
       variable of type signed long.  It should be possible to evaluate the expression at
       compile-time. If no includes are specified, the default includes are used.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.

   check_sizeof_type( $type, \%options? )
       Checks for the size of the specified type by compiling and define "SIZEOF_type" using the
       determined size.

       In opposition to GNU AutoConf, this method can determine size of structure members, eg.

         $ac->check_sizeof_type( "SV.sv_refcnt", { prologue => $include_perl } );
         # or
         $ac->check_sizeof_type( "struct utmpx.ut_id", { prologue => "#include <utmpx.h>" } );

       This method caches its result in the "ac_cv_sizeof_<set lang>"_type variable.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.

   check_sizeof_types( type, \%options? )
       For each type check_sizeof_type is called to check for size of type.

       If action-if-found is given, it is additionally executed when all of the sizes of the
       types could determined. If action-if-not-found is given, it is executed when one size of
       the types could not determined.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.  Given callbacks for action_on_size_true or
       action_on_size_false are called for each symbol checked using "check_sizeof_type"
       receiving the symbol as first argument.

   check_alignof_type( type, \%options? )
       Define ALIGNOF_type to be the alignment in bytes of type. type must be valid as a
       structure member declaration or type must be a structure member itself.

       This method caches its result in the "ac_cv_alignof_<set lang>"_type variable, with *
       mapped to "p" and other characters not suitable for a variable name mapped to underscores.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.

   check_alignof_types (type, [action-if-found], [action-if-not-found], [prologue = default
       includes])
       For each type check_alignof_type is called to check for align of type.

       If action-if-found is given, it is additionally executed when all of the aligns of the
       types could determined. If action-if-not-found is given, it is executed when one align of
       the types could not determined.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.  Given callbacks for action_on_align_true or
       action_on_align_false are called for each symbol checked using "check_alignof_type"
       receiving the symbol as first argument.

   check_member( member, \%options? )
       Check whether member is in form of aggregate.member and member is a member of the
       aggregate aggregate.

       which are used prior to the aggregate under test.

         Config::AutoConf->check_member(
           "struct STRUCT_SV.sv_refcnt",
           {
             action_on_false => sub { Config::AutoConf->msg_failure( "sv_refcnt member required for struct STRUCT_SV" ); },
             prologue => "#include <EXTERN.h>\n#include <perl.h>"
           }
         );

       This function will return a true value (1) if the member is found.

       If aggregate aggregate has member member, preprocessor macro HAVE_aggregate_MEMBER (in all
       capitals, with spaces and dots replaced by underscores) is defined.

       This macro caches its result in the "ac_cv_"aggr_member variable.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.

   check_members( members, \%options? )
       For each member check_member is called to check for member of aggregate.

       This function will return a true value (1) if at least one member is found.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be favoured over "default includes" (represented by
       "_default_includes"). If any of action_on_cache_true, action_on_cache_false is defined,
       both callbacks are passed to "check_cached" as action_on_true or action_on_false to
       "check_cached", respectively.  Given callbacks for action_on_member_true or
       action_on_member_false are called for each symbol checked using "check_member" receiving
       the symbol as first argument.

   check_header( $header, \%options? )
       This function is used to check if a specific header file is present in the system: if we
       detect it and if we can compile anything with that header included. Note that normally you
       want to check for a header first, and then check for the corresponding library (not all at
       once).

       The standard usage for this module is:

         Config::AutoConf->check_header("ncurses.h");

       This function will return a true value (1) on success, and a false value if the header is
       not present or not available for common usage.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  When a prologue exists in the optional
       hash at end, it will be prepended to the tested header. If any of action_on_cache_true,
       action_on_cache_false is defined, both callbacks are passed to "check_cached" as
       action_on_true or action_on_false to "check_cached", respectively.

   check_headers
       This function uses check_header to check if a set of include files exist in the system and
       can be included and compiled by the available compiler.  Returns the name of the first
       header file found.

       Passes an optional \%options hash to each "check_header" call.

   check_all_headers
       This function checks each given header for usability and returns true when each header can
       be used -- otherwise false.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  Each of existing key/value pairs using
       prologue, action_on_cache_true or action_on_cache_false as key are passed-through to each
       call of "check_header".  Given callbacks for action_on_header_true or
       action_on_header_false are called for each symbol checked using "check_header" receiving
       the symbol as first argument.

   check_stdc_headers
       Checks for standard C89 headers, namely stdlib.h, stdarg.h, string.h and float.h.  If
       those are found, additional all remaining C89 headers are checked: assert.h, ctype.h,
       errno.h, limits.h, locale.h, math.h, setjmp.h, signal.h, stddef.h, stdio.h and time.h.

       Returns a false value if it fails.

       Passes an optional \%options hash to each "check_all_headers" call.

   check_default_headers
       This function checks for some default headers, the std c89 headers and sys/types.h,
       sys/stat.h, memory.h, strings.h, inttypes.h, stdint.h and unistd.h

       Passes an optional \%options hash to each "check_all_headers" call.

   check_dirent_header
       Check for the following header files. For the first one that is found and defines 'DIR',
       define the listed C preprocessor macro:

         dirent.h      HAVE_DIRENT_H
         sys/ndir.h    HAVE_SYS_NDIR_H
         sys/dir.h     HAVE_SYS_DIR_H
         ndir.h        HAVE_NDIR_H

       The directory-library declarations in your source code should look something like the
       following:

         #include <sys/types.h>
         #ifdef HAVE_DIRENT_H
         # include <dirent.h>
         # define NAMLEN(dirent) strlen ((dirent)->d_name)
         #else
         # define dirent direct
         # define NAMLEN(dirent) ((dirent)->d_namlen)
         # ifdef HAVE_SYS_NDIR_H
         #  include <sys/ndir.h>
         # endif
         # ifdef HAVE_SYS_DIR_H
         #  include <sys/dir.h>
         # endif
         # ifdef HAVE_NDIR_H
         #  include <ndir.h>
         # endif
         #endif

       Using the above declarations, the program would declare variables to be of type "struct
       dirent", not "struct direct", and would access the length of a directory entry name by
       passing a pointer to a "struct dirent" to the "NAMLEN" macro.

       This method might be obsolescent, as all current systems with directory libraries have
       "<<dirent.h>">. Programs supporting only newer OS might not need to use this method.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  Each of existing key/value pairs using
       prologue, action_on_header_true (as action_on_true having the name of the tested header as
       first argument) or action_on_header_false (as action_on_false having the name of the
       tested header as first argument) as key are passed-through to each call of
       "_check_header".  Given callbacks for action_on_cache_true or action_on_cache_false are
       passed to the call of "check_cached".

   _check_perlapi_program
       This method provides the program source which is suitable to do basic compile/link tests
       to prove perl development environment.

   _check_compile_perlapi
       This method can be used from other checks to prove whether we have a perl development
       environment or not (perl.h, reasonable basic checks - types, etc.)

   check_compile_perlapi
       This method can be used from other checks to prove whether we have a perl development
       environment or not (perl.h, reasonable basic checks - types, etc.)

   check_compile_perlapi_or_die
       Dies when not being able to compile using the Perl API

   check_linkable_xs_so
       Checks whether a dynamic loadable object containing an XS module can be linked or not. Due
       the nature of the beast, this test currently always succeed.

   check_linkable_xs_so_or_die
       Dies when "check_linkable_xs_so" fails.

   check_loadable_xs_so
       Checks whether a dynamic loadable object containing an XS module can be loaded or not. Due
       the nature of the beast, this test currently always succeed.

   check_loadable_xs_so_or_die
       Dies when "check_loadable_xs_so" fails.

   _check_link_perlapi
       This method can be used from other checks to prove whether we have a perl development
       environment including a suitable libperl or not (perl.h, reasonable basic checks - types,
       etc.)

       Caller must ensure that the linker flags are set appropriate ("-lperl" or similar).

   check_link_perlapi
       This method can be used from other checks to prove whether we have a perl development
       environment or not (perl.h, libperl.la, reasonable basic checks - types, etc.)

   check_lib( lib, func, @other-libs?, \%options? )
       This function is used to check if a specific library includes some function. Call it with
       the library name (without the lib portion), and the name of the function you want to test:

         Config::AutoConf->check_lib("z", "gzopen");

       It returns 1 if the function exist, 0 otherwise.

       In case of function found, the HAVE_LIBlibrary (all in capitals) preprocessor macro is
       defined with 1 and $lib together with @other_libs are added to the list of libraries to
       link with.

       If linking with library results in unresolved symbols that would be resolved by linking
       with additional libraries, give those libraries as the other-libs argument: e.g., "[qw(Xt
       X11)]".  Otherwise, this routine may fail to detect that library is present, because
       linking the test program can fail with unresolved symbols.  The other-libraries argument
       should be limited to cases where it is desirable to test for one library in the presence
       of another that is not already in LIBS.

       This method caches its result in the "ac_cv_lib_"lib_func variable.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  If any of action_on_cache_true,
       action_on_cache_false is defined, both callbacks are passed to "check_cached" as
       action_on_true or action_on_false to "check_cached", respectively.

       It's recommended to use search_libs instead of check_lib these days.

   search_libs( function, search-libs, @other-libs?, \%options? )
       Search for a library defining function if it's not already available.  This equates to
       calling

           Config::AutoConf->link_if_else(
               Config::AutoConf->lang_call( "", "$function" ) );

       first with no libraries, then for each library listed in search-libs.  search-libs must be
       specified as an array reference to avoid confusion in argument order.

       Prepend -llibrary to LIBS for the first library found to contain function.

       If linking with library results in unresolved symbols that would be resolved by linking
       with additional libraries, give those libraries as the other-libraries argument: e.g.,
       "[qw(Xt X11)]". Otherwise, this method fails to detect that function is present, because
       linking the test program always fails with unresolved symbols.

       The result of this test is cached in the ac_cv_search_function variable as "none required"
       if function is already available, as 0 if no library containing function was found,
       otherwise as the -llibrary option that needs to be prepended to LIBS.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  If any of action_on_cache_true,
       action_on_cache_false is defined, both callbacks are passed to "check_cached" as
       action_on_true or action_on_false to "check_cached", respectively.  Given callbacks for
       action_on_lib_true or action_on_lib_false are called for each library checked using
       "link_if_else" receiving the library as first argument and all @other_libs subsequently.

   check_lm( \%options? )
       This method is used to check if some common "math.h" functions are available, and if "-lm"
       is needed. Returns the empty string if no library is needed, or the "-lm" string if libm
       is needed.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  Each of existing key/value pairs using
       action_on_func_true (as action_on_true having the name of the tested functions as first
       argument), action_on_func_false (as action_on_false having the name of the tested
       functions as first argument), action_on_func_lib_true (as action_on_lib_true having the
       name of the tested functions as first argument), action_on_func_lib_false (as
       action_on_lib_false having the name of the tested functions as first argument) as key are
       passed- through to each call of "search_libs".  Given callbacks for action_on_lib_true,
       action_on_lib_false, action_on_cache_true or action_on_cache_false are passed to the call
       of "search_libs".

       Note that action_on_lib_true and action_on_func_lib_true or action_on_lib_false and
       action_on_func_lib_false cannot be used at the same time, respectively.

   pkg_config_package_flags($package, \%options?)
       Search for pkg-config flags for package as specified. The flags which are extracted are
       "--cflags" and "--libs". The extracted flags are appended to the global
       "extra_compile_flags" and "extra_link_flags", respectively.

       Call it with the package you're looking for and optional callback whether found or not.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.  If any of action_on_cache_true,
       action_on_cache_false is defined, both callbacks are passed to "check_cached" as
       action_on_true or action_on_false to "check_cached", respectively.

   _check_mm_pureperl_build_wanted
       This method proves the "_argv" attribute and (when set) the "PERL_MM_OPT" whether they
       contain PUREPERL_ONLY=(0|1) or not. The attribute "_force_xs" is set as appropriate, which
       allows a compile test to bail out when "Makefile.PL" is called with PUREPERL_ONLY=0.

   _check_mb_pureperl_build_wanted
       This method proves the "_argv" attribute and (when set) the "PERL_MB_OPT" whether they
       contain --pureperl-only or not.

   _check_pureperl_required
       This method calls "_check_mm_pureperl_build_wanted" when running under ExtUtils::MakeMaker
       ("Makefile.PL") or "_check_mb_pureperl_build_wanted" when running under a "Build.PL"
       (Module::Build compatible) environment.

       When neither is found ($0 contains neither "Makefile.PL" nor "Build.PL"), simply 0 is
       returned.

   check_pureperl_required
       This check method proves whether a pureperl build is wanted or not by cached-checking
       "$self->_check_pureperl_required".

   check_produce_xs_build
       This routine checks whether XS can be produced. Therefore it does following checks in
       given order:

       •   check pureperl environment variables ("check_pureperl_required") or command line
           arguments and return false when pure perl is requested

       •   check whether a compiler is available ("check_valid_compilers") and return false if
           none found

       •   check whether a test program accessing Perl API can be compiled and die with error if
           not

       When all checks passed successfully, return a true value.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.

   check_produce_loadable_xs_build
       This routine proves whether XS should be built and it's possible to create a dynamic
       linked object which can be loaded using Perl's Dynaloader.

       The extension over "check_produce_xs_build" can be avoided by adding the
       "notest_loadable_xs" to $ENV{PERL5_AC_OPTS}.

       If the very last parameter contains a hash reference, "CODE" references to action_on_true
       or action_on_false are executed, respectively.

   _set_argv
       Intended to act as a helper for evaluating given command line arguments.  Stores given
       arguments in instances "_argv" attribute.

       Call once at very begin of "Makefile.PL" or "Build.PL":

         Your::Pkg::Config::AutoConf->_set_args(@ARGV);

   _default_includes
       returns a string containing default includes for program prologue taken from
       autoconf/headers.m4:

         #include <stdio.h>
         #ifdef HAVE_SYS_TYPES_H
         # include <sys/types.h>
         #endif
         #ifdef HAVE_SYS_STAT_H
         # include <sys/stat.h>
         #endif
         #ifdef STDC_HEADERS
         # include <stdlib.h>
         # include <stddef.h>
         #else
         # ifdef HAVE_STDLIB_H
         #  include <stdlib.h>
         # endif
         #endif
         #ifdef HAVE_STRING_H
         # if !defined STDC_HEADERS && defined HAVE_MEMORY_H
         #  include <memory.h>
         # endif
         # include <string.h>
         #endif
         #ifdef HAVE_STRINGS_H
         # include <strings.h>
         #endif
         #ifdef HAVE_INTTYPES_H
         # include <inttypes.h>
         #endif
         #ifdef HAVE_STDINT_H
         # include <stdint.h>
         #endif
         #ifdef HAVE_UNISTD_H
         # include <unistd.h>
         #endif

   _default_includes_with_perl
       returns a string containing default includes for program prologue containing
       _default_includes plus

         #include <EXTERN.h>
         #include <perl.h>

   add_log_fh
       Push new file handles at end of log-handles to allow tee-ing log-output

   delete_log_fh
       Removes specified log file handles. This method allows you to shoot yourself in the foot -
       it doesn't prove whether the primary nor the last handle is removed. Use with caution.

AUTHOR

       Alberto Simo~es, "<ambs@cpan.org>"

       Jens Rehsack, "<rehsack@cpan.org>"

NEXT STEPS

       Although a lot of work needs to be done, these are the next steps I intend to take.

         - detect flex/lex
         - detect yacc/bison/byacc
         - detect ranlib (not sure about its importance)

       These are the ones I think not too much important, and will be addressed later, or by
       request.

         - detect an 'install' command
         - detect a 'ln -s' command -- there should be a module doing
           this kind of task.

BUGS

       A lot. Portability is a pain. <Patches welcome!>.

       Please report any bugs or feature requests to "bug-Config-AutoConf@rt.cpan.org", or
       through the web interface at <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Config-AutoConf>.
       We will be notified, and then you'll automatically be notified of progress on your bug as
       we make changes.

SUPPORT

       You can find documentation for this module with the perldoc command.

           perldoc Config::AutoConf

       You can also look for information at:

       •   AnnoCPAN: Annotated CPAN documentation

           <http://annocpan.org/dist/Config-AutoConf>

       •   CPAN Ratings

           <http://cpanratings.perl.org/l/Config-AutoConf>

       •   MetaCPAN

           <https://metacpan.org/release/Config-AutoConf>

       •   Git Repository

           <https://github.com/ambs/Config-AutoConf>

ACKNOWLEDGEMENTS

       Michael Schwern for kind MacOS X help.

       Ken Williams for ExtUtils::CBuilder

       Peter Rabbitson for help on refactoring and making the API more Perl'ish

COPYRIGHT & LICENSE

       Copyright 2004-2015 by the Authors

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

SEE ALSO

       ExtUtils::CBuilder(3)