NAME

       Imager::Probe - hot needle of inquiry for libraries

SYNOPSIS

         require Imager::Probe;

         my %probe =
           (
            # short name of what we're looking for (displayed to user)
            name => "FOO",
            # pkg-config lookup
            pkg => [ qw/name1 name2 name3/ ],
            # perl subs that probe for the library
            code => [ \&foo_probe1, \&foo_probe2 ],
            # or just: code => \&foo_probe,
            inccheck => sub { ... },
            libcheck => sub { ... },
            # search for this library if libcheck not supplied
            libbase => "foo",
            # library link time options, uses libbase to build options otherwise
            libopts => "-lfoo",
            # C code to check the library is sane
            testcode => "...",
            # header files needed
            testcodeheaders => [ "stdio.h", "foo.h" ],
           );
         my $result = Imager::Probe->probe(\%probe)
           or print "Foo library not found: ",Imager::Probe->error;

DESCRIPTION

       Does the probes that were hidden in Imager's Makefile.PL, pulled out so the file format
       libraries can be externalized.

       The return value is either nothing if the probe fails, or a hash containing:

       •   "INC" - "-I" and other C options

       •   "LIBS" - "-L", "-l" and other link-time options

       •   "DEFINE" - "-D" options, if any.

       The possible values for the hash supplied to the probe() method are:

       •   "pkg" - an array of pkg-config names to probe for.  If the pkg-config checks pass,
           "inccheck" and "libcheck" aren't used.

       •   "inccheck" - a code reference that checks if the supplied include directory contains
           the required header files.

       •   "libcheck" - a code reference that checks if the supplied library directory contains
           the required library files.  Note: the Makefile.PL version of this was supplied all of
           the library file names instead.  "libcheck" can also be an arrayref of library check
           code references, all of which must find a match for the library to be considered
           "found".

       •   "libbase" - if "inccheck" is supplied, but "libcheck" isn't, then a "libcheck" that
           checks for "lib"libbase$Config{_a} and "lib"libbase.$Config{so} is created.  If
           "libopts" isn't supplied then that can be synthesized as "-llibbase". "libbase" can
           also be an arrayref of library base names to search for, in which case all of the
           libraries mentioned must be found for the probe to succeed.

       •   "libopts" - if the libraries are found via "inccheck"/"libcheck", these are the "-l"
           options to supply during the link phase.

       •   "code" - a code reference to perform custom checks.  Returns the probe result
           directly.  Can also be an array ref of functions to call.

       •   "testcode" - test C code that is run with Devel::CheckLib.  You also need to set
           "testcodeheaders".

       •   "testcodeprologue" - C code to insert between the headers and the main function.

       •   "incpath" - $Config{path_sep} separated list of header file directories to check, or a
           reference to an array of such.

       •   "libpath" - $Config{path_sep} separated list of library file directories to check, or
           a reference to an array of such.

       •   "alternatives" - an optional array reference of alternate configurations (as hash
           references) to test if the primary configuration isn't successful.  Each alternative
           should include an "altname" key describing the alternative.  Any key not mentioned in
           an alternative defaults to the value from the main configuration.

AUTHOR

       Tony Cook <tonyc@cpan.org>, Arnar M. Hrafnkelsson