NAME

    FFI::CheckLib - Check that a library is available for FFI

VERSION

    version 0.26

SYNOPSIS

     use FFI::CheckLib;
     
     check_lib_or_exit( lib => 'jpeg', symbol => 'jinit_memory_mgr' );
     check_lib_or_exit( lib => [ 'iconv', 'jpeg' ] );
     
     # or prompt for path to library and then:
     print "where to find jpeg library: ";
     my $path = <STDIN>;
     check_lib_or_exit( lib => 'jpeg', libpath => $path );

DESCRIPTION

    This module checks whether a particular dynamic library is available
    for FFI to use. It is modeled heavily on Devel::CheckLib, but will find
    dynamic libraries even when development packages are not installed. It
    also provides a find_lib function that will return the full path to the
    found dynamic library, which can be feed directly into FFI::Platypus or
    another FFI system.

    Although intended mainly for FFI modules via FFI::Platypus and similar,
    this module does not actually use any FFI to do its detection and
    probing. This module does not have any non-core runtime dependencies.
    The test suite does depend on Test2::Suite.

FUNCTIONS

    All of these take the same named parameters and are exported by
    default.

 find_lib

     my(@libs) = find_lib(%args);

    This will return a list of dynamic libraries, or empty list if none
    were found.

    [version 0.05]

    If called in scalar context it will return the first library found.

    Arguments are key value pairs with these keys:

    lib

      Must be either a string with the name of a single library or a
      reference to an array of strings of library names. Depending on your
      platform, CheckLib will prepend lib or append .dll or .so when
      searching.

      [version 0.11]

      As a special case, if * is specified then any libs found will match.

    libpath

      A string or array of additional paths to search for libraries.

    systempath

      [version 0.11]

      A string or array of system paths to search for instead of letting
      FFI::CheckLib determine the system path. You can set this to [] in
      order to not search any system paths.

    symbol

      A string or a list of symbol names that must be found.

    verify

      A code reference used to verify a library really is the one that you
      want. It should take two arguments, which is the name of the library
      and the full path to the library pathname. It should return true if
      it is acceptable, and false otherwise. You can use this in
      conjunction with FFI::Platypus to determine if it is going to meet
      your needs. Example:

       use FFI::CheckLib;
       use FFI::Platypus;
       
       my($lib) = find_lib(
         lib => 'foo',
         verify => sub {
           my($name, $libpath) = @_;
       
           my $ffi = FFI::Platypus->new;
           $ffi->lib($libpath);
       
           my $f = $ffi->function('foo_version', [] => 'int');
       
           return $f->call() >= 500; # we accept version 500 or better
         },
       );

    recursive

      [version 0.11]

      Recursively search for libraries in any non-system paths (those
      provided via libpath above).

    try_linker_script

      [version 0.24]

      Some vendors provide .so files that are linker scripts that point to
      the real binary shared library. These linker scripts can be used by
      gcc or clang, but are not directly usable by FFI::Platypus and
      friends. On select platforms, this options will use the linker
      command (ld) to attempt to resolve the real .so for non-binary files.
      Since there is extra overhead this is off by default.

      An example is libyaml on Red Hat based Linux distributions. On Debian
      these are handled with symlinks and no trickery is required.

    alien

      [version 0.25]

      If no libraries can be found, try the given aliens instead. The Alien
      classes specified must provide the Alien::Base interface for dynamic
      libraries, which is to say they should provide a method called
      dynamic_libs that returns a list of dynamic libraries.

 assert_lib

     assert_lib(%args);

    This behaves exactly the same as find_lib, except that instead of
    returning empty list of failure it throws an exception.

 check_lib_or_exit

     check_lib_or_exit(%args);

    This behaves exactly the same as assert_lib, except that instead of
    dying, it warns (with exactly the same error message) and exists. This
    is intended for use in Makefile.PL or Build.PL

 find_lib_or_exit

    [version 0.05]

     my(@libs) = find_lib_or_exit(%args);

    This behaves exactly the same as find_lib, except that if the library
    is not found, it will call exit with an appropriate diagnostic.

 find_lib_or_die

    [version 0.06]

     my(@libs) = find_lib_or_die(%args);

    This behaves exactly the same as find_lib, except that if the library
    is not found, it will die with an appropriate diagnostic.

 check_lib

     my $bool = check_lib(%args);

    This behaves exactly the same as find_lib, except that it returns true
    (1) on finding the appropriate libraries or false (0) otherwise.

 which

    [version 0.17]

     my $path = where($name);

    Return the path to the first library that matches the given name.

    Not exported by default.

 where

    [version 0.17]

     my @paths = where($name);

    Return the paths to all the libraries that match the given name.

    Not exported by default.

 has_symbols

    [version 0.17]

     my $bool = has_symbols($path, @symbol_names);

    Returns true if all of the symbols can be found in the dynamic library
    located at the given path. Can be useful in conjunction with verify
    with find_lib above.

    Not exported by default.

 system_path

    [version 0.20]

     my $path = FFI::CheckLib::system_path;

    Returns the system path as a list reference. On some systems, this is
    PATH on others it might be LD_LIBRARY_PATH on still others it could be
    something completely different. So although you may add items to this
    list, you should probably do some careful consideration before you do
    so.

    This function is not exportable, even on request.

SEE ALSO

    FFI::Platypus

      Call library functions dynamically without a compiler.

    Dist::Zilla::Plugin::FFI::CheckLib

      Dist::Zilla plugin for this module.

AUTHOR

    Author: Graham Ollis <plicease@cpan.org>

    Contributors:

    Bakkiaraj Murugesan (bakkiaraj)

    Dan Book (grinnz, DBOOK)

    Ilya Pavlov (Ilya, ILUX)

    Shawn Laffan (SLAFFAN)

    Petr Pisar (ppisar)

COPYRIGHT AND LICENSE

    This software is copyright (c) 2014-2018 by Graham Ollis.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

