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.\" ========================================================================
.\"
.IX Title "FFI::CheckLib 3pm"
.TH FFI::CheckLib 3pm "2018-11-25" "perl v5.28.0" "User Contributed Perl Documentation"
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.nh
.SH "NAME"
FFI::CheckLib \- Check that a library is available for FFI
.SH "VERSION"
.IX Header "VERSION"
version 0.23
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& use FFI::CheckLib;
\& 
\& check_lib_or_exit( lib => \*(Aqjpeg\*(Aq, symbol => \*(Aqjinit_memory_mgr\*(Aq );
\& check_lib_or_exit( lib => [ \*(Aqiconv\*(Aq, \*(Aqjpeg\*(Aq ] );
\& 
\& # or prompt for path to library and then:
\& print "where to find jpeg library: ";
\& my $path = <STDIN>;
\& check_lib_or_exit( lib => \*(Aqjpeg\*(Aq, libpath => $path );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module checks whether a particular dynamic library is available for
\&\s-1FFI\s0 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 \s-1FFI\s0 system.
.PP
Although intended mainly for \s-1FFI\s0 modules via FFI::Platypus and
similar, this module does not actually use any \s-1FFI\s0 to do its detection
and probing.  This module does not have any non-core runtime dependencies.
The test suite does depend on Test2::Suite.
.SH "FUNCTIONS"
.IX Header "FUNCTIONS"
All of these take the same named parameters and are exported by default.
.SS "find_lib"
.IX Subsection "find_lib"
.Vb 1
\& my(@libs) = find_lib(%args);
.Ve
.PP
This will return a list of dynamic libraries, or empty list if none were
found.
.PP
[version 0.05]
.PP
If called in scalar context it will return the first library found.
.PP
Arguments are key value pairs with these keys:
.IP "lib" 4
.IX 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 your platform,
\&\f(CW\*(C`CheckLib\*(C'\fR will prepend \f(CW\*(C`lib\*(C'\fR or append \f(CW\*(C`.dll\*(C'\fR or \f(CW\*(C`.so\*(C'\fR when
searching.
.Sp
[version 0.11]
.Sp
As a special case, if \f(CW\*(C`*\*(C'\fR is specified then any libs found will match.
.IP "libpath" 4
.IX Item "libpath"
A string or array of additional paths to search for libraries.
.IP "systempath" 4
.IX Item "systempath"
[version 0.11]
.Sp
A string or array of system paths to search for instead of letting
FFI::CheckLib determine the system path.  You can set this to \f(CW\*(C`[]\*(C'\fR
in order to not search \fIany\fR system paths.
.IP "symbol" 4
.IX Item "symbol"
A string or a list of symbol names that must be found.
.IP "verify" 4
.IX Item "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:
.Sp
.Vb 2
\& use FFI::CheckLib;
\& use FFI::Platypus;
\& 
\& my($lib) = find_lib(
\&   lib => \*(Aqfoo\*(Aq,
\&   verify => sub {
\&     my($name, $libpath) = @_;
\&     
\&     my $ffi = FFI::Platypus\->new;
\&     $ffi\->lib($libpath);
\&     
\&     my $f = $ffi\->function(\*(Aqfoo_version\*(Aq, [] => \*(Aqint\*(Aq);
\&     
\&     return $f\->call() >= 500; # we accept version 500 or better
\&   },
\& );
.Ve
.IP "recursive" 4
.IX Item "recursive"
[version 0.11]
.Sp
Recursively search for libraries in any non-system paths (those provided
via \f(CW\*(C`libpath\*(C'\fR above).
.SS "assert_lib"
.IX Subsection "assert_lib"
.Vb 1
\& assert_lib(%args);
.Ve
.PP
This behaves exactly the same as find_lib,
except that instead of returning empty list of failure it throws an
exception.
.SS "check_lib_or_exit"
.IX Subsection "check_lib_or_exit"
.Vb 1
\& check_lib_or_exit(%args);
.Ve
.PP
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 \f(CW\*(C`Makefile.PL\*(C'\fR or
\&\f(CW\*(C`Build.PL\*(C'\fR
.SS "find_lib_or_exit"
.IX Subsection "find_lib_or_exit"
[version 0.05]
.PP
.Vb 1
\& my(@libs) = find_lib_or_exit(%args);
.Ve
.PP
This behaves exactly the same as find_lib,
except that if the library is not found, it will call exit with an
appropriate diagnostic.
.SS "find_lib_or_die"
.IX Subsection "find_lib_or_die"
[version 0.06]
.PP
.Vb 1
\& my(@libs) = find_lib_or_die(%args);
.Ve
.PP
This behaves exactly the same as find_lib,
except that if the library is not found, it will die with an appropriate
diagnostic.
.SS "check_lib"
.IX Subsection "check_lib"
.Vb 1
\& my $bool = check_lib(%args);
.Ve
.PP
This behaves exactly the same as find_lib,
except that it returns true (1) on finding the appropriate libraries or
false (0) otherwise.
.SS "which"
.IX Subsection "which"
[version 0.17]
.PP
.Vb 1
\& my $path = where($name);
.Ve
.PP
Return the path to the first library that matches the given name.
.PP
Not exported by default.
.SS "where"
.IX Subsection "where"
[version 0.17]
.PP
.Vb 1
\& my @paths = where($name);
.Ve
.PP
Return the paths to all the libraries that match the given name.
.PP
Not exported by default.
.SS "has_symbols"
.IX Subsection "has_symbols"
[version 0.17]
.PP
.Vb 1
\& my $bool = has_symbols($path, @symbol_names);
.Ve
.PP
Returns true if \fIall\fR of the symbols can be found in the dynamic library located
at the given path.  Can be useful in conjunction with \f(CW\*(C`verify\*(C'\fR with \f(CW\*(C`find_lib\*(C'\fR
above.
.PP
Not exported by default.
.SS "system_path"
.IX Subsection "system_path"
[version 0.20]
.PP
.Vb 1
\& my $path = FFI::CheckLib::system_path;
.Ve
.PP
Returns the system path as a list reference.  On some systems, this is \f(CW\*(C`PATH\*(C'\fR
on others it might be \s-1LD_LIBRARY_PATH\s0 on still others it could be something
completely different.  So although you \fImay\fR add items to this list, you should
probably do some careful consideration before you do so.
.PP
This function is not exportable, even on request.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
.IP "FFI::Platypus" 4
.IX Item "FFI::Platypus"
Call library functions dynamically without a compiler.
.IP "Dist::Zilla::Plugin::FFI::CheckLib" 4
.IX Item "Dist::Zilla::Plugin::FFI::CheckLib"
Dist::Zilla plugin for this module.
.SH "AUTHOR"
.IX Header "AUTHOR"
Author: Graham Ollis <plicease@cpan.org>
.PP
Contributors:
.PP
Bakkiaraj Murugesan (bakkiaraj)
.PP
Dan Book (grinnz, \s-1DBOOK\s0)
.PP
Ilya Pavlov (Ilya, \s-1ILUX\s0)
.PP
Shawn Laffan (\s-1SLAFFAN\s0)
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This software is copyright (c) 2014\-2018 by Graham Ollis.
.PP
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.