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# $Id: CheckLib.pm,v 1.25 2008/10/27 12:16:23 drhyde Exp $

package #
Devel::CheckLib;

use 5.00405; #postfix foreach
use strict;
use vars qw($VERSION @ISA @EXPORT);
$VERSION = '0.98';
use Config qw(%Config);
use Text::ParseWords 'quotewords';

use File::Spec;
use File::Temp;

require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(assert_lib check_lib_or_exit check_lib);

# localising prevents the warningness leaking out of this module
local $^W = 1;    # use warnings is a 5.6-ism

_findcc(); # bomb out early if there's no compiler

=head1 NAME

Devel::CheckLib - check that a library is available

=head1 DESCRIPTION

Devel::CheckLib is a perl module that checks whether a particular C
library and its headers are available.

=head1 SYNOPSIS

    use Devel::CheckLib;

    check_lib_or_exit( lib => 'jpeg', header => 'jpeglib.h' );
    check_lib_or_exit( lib => [ 'iconv', 'jpeg' ] );
  
    # or prompt for path to library and then do this:
    check_lib_or_exit( lib => 'jpeg', libpath => $additional_path );

=head1 USING IT IN Makefile.PL or Build.PL

If you want to use this from Makefile.PL or Build.PL, do
not simply copy the module into your distribution as this may cause
problems when PAUSE and search.cpan.org index the distro.  Instead, use
the use-devel-checklib script.

=head1 HOW IT WORKS

You pass named parameters to a function, describing to it how to build
and link to the libraries.

It works by trying to compile some code - which defaults to this:

    int main(void) { return 0; }

and linking it to the specified libraries.  If something pops out the end
which looks executable, it gets executed, and if main() returns 0 we know
that it worked.  That tiny program is
built once for each library that you specify, and (without linking) once
for each header file.

If you want to check for the presence of particular functions in a
library, or even that those functions return particular results, then
you can pass your own function body for main() thus:

    check_lib_or_exit(
        function => 'foo();if(libversion() > 5) return 0; else return 1;'
        incpath  => ...
        libpath  => ...
        lib      => ...
        header   => ...
    );

In that case, it will fail to build if either foo() or libversion() don't
exist, and main() will return the wrong value if libversion()'s return
value isn't what you want.

=head1 FUNCTIONS

All of these take the same named parameters and are exported by default.
To avoid exporting them, C<use Devel::CheckLib ()>.

=head2 assert_lib

This takes several named parameters, all of which are optional, and dies
with an error message if any of the libraries listed can
not be found.  B<Note>: dying in a Makefile.PL or Build.PL may provoke
a 'FAIL' report from CPAN Testers' automated smoke testers.  Use 
C<check_lib_or_exit> instead.

The named parameters are:

=over

=item 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 the compiler found, library names will be fed to the compiler either as
C<-l> arguments or as C<.lib> file names.  (E.g. C<-ljpeg> or C<jpeg.lib>)

=item libpath

a string or an array of strings
representing additional paths to search for libraries.

=item LIBS

a C<ExtUtils::MakeMaker>-style space-seperated list of
libraries (each preceded by '-l') and directories (preceded by '-L').

This can also be supplied on the command-line.

=back

And libraries are no use without header files, so ...