Config::AutoConf(3)

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.

CONSTRUCTOR

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

METHODS

  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 GNU Autoconf <https://www.gnu.org/software/autoconf/autoconf.html> 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 GNU Autoconf <https://www.gnu.org/software/autoconf/autoconf.html> 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 GNU Autoconf <https://www.gnu.org/software/autoconf/autoconf.html> 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 GNU Autoconf <https://www.gnu.org/software/autoconf/autoconf.html> documentation,

  If flex is found, set output [...] to ‘flex’ and [...] to -lfl, if that
  library is in a standard place. Otherwise set output [...] to ‘lex’ 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 GNU Autoconf <https://www.gnu.org/software/autoconf/autoconf.html> 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_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_call( [prologue], function )
Builds program which simply calls given function. When given, prologue is prepended otherwise, the default includes are used.

  lang_builtin( [prologue], builtin )
Builds program which simply proves whether a builtin is known to language compiler.

  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 favored 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 favored 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_builtin( $builtin, \%options? )
This method actually tests whether $builtin is a supported built-in known by the compiler. Either, by giving us the type of the built-in or by taking the value from "__has_builtin". This method caches its result in the ac_cv_builtin_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_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 favored 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 favored 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 favored 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, e.g.

  $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 favored 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 favored 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 favored 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 favored 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 favored 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 favored 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.

For the found header, the macro HAVE_DIRENT_IN_${header} is defined.

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?, @extra_link_flags?, \%options? )
    Config::AutoConf->search_libs("gethostent", "nsl", [qw(socket net)], {
        action_on_true => sub { ... }
    });
    Config::AutoConf->search_libs("log4cplus_initialize", ["log4cplus"],
        [[qw(stdc++)], [qw(stdc++ unwind)]],
        [qw(-pthread -thread)]
    );

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)]" or "[qw(intl), qw(intl iconv)]". 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?)
  use Config::AutoConf

  my $c = Config::AutoConf->new;
  $c->pkg_config_package_flags('log4cplus');
  WriteMakefile(
    ...
    INC  => $c->_get_extra_compiler_flags,
    LIBS => $c->_get_extra_linker_flags,
  );

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_preprocess_flags", "extra_link_flags" or "extra_libs", respectively. Distinguishing between "extra_link_flags" and "extra_libs" is essential to avoid conflicts with search_libs function and family. In case, no package configuration matching given criteria could be found, return a "false" value (0).

The "pkg-config" flags are taken from environment variables "${package}_CFLAGS" or "${package}_LIBS" when defined, respectively. It will be a nice touch to document the particular environment variables for your build procedure - as for above example it should be

  $ env log4cplus_CFLAGS="-I/opt/coolapp/include" \
        log4cplus_LIBS="-L/opt/coolapp/lib -Wl,-R/opt/coolapp/lib -llog4cplus" \
    perl Makefile.PL

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

To support stage compiling properly ("rpath" vs. library file location), the internal representation is a moving target. Do not use the result directly - the getters _get_extra_compiler_flags and _get_extra_linker_flags are strongly encouraged. In case this is not possible, please open a ticket to get informed on invasive changes.

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 pure perl 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 pure perl 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.

  _get_extra_compiler_flags
Returns the determined flags required to run the compile stage as string

  _get_extra_linker_flags
Returns the determined flags required to run the link stage as string

AUTHOR
Alberto Simões, "<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/dist/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 2004-2020 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)