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lib(3pm)               Perl Programmers Reference Guide               lib(3pm)




NAME

       lib - manipulate @INC at compile time


SYNOPSIS

           use lib LIST;

           no lib LIST;


DESCRIPTION

       This is a small simple module which simplifies the manipulation of @INC
       at compile time.

       It is typically used to add extra directories to perl's search path so
       that later "use" or "require" statements will find modules which are
       not located on perl's default search path.

   Adding directories to @INC
       The parameters to "use lib" are added to the start of the perl search
       path. Saying

           use lib LIST;

       is almost the same as saying

           BEGIN { unshift(@INC, LIST) }

       For each directory in LIST (called $dir here) the lib module also
       checks to see if a directory called $dir/$archname/auto exists.  If so
       the $dir/$archname directory is assumed to be a corresponding
       architecture specific directory and is added to @INC in front of $dir.
       lib.pm also checks if directories called $dir/$version and
       $dir/$version/$archname exist and adds these directories to @INC.

       The current value of $archname can be found with this command:

           perl -V:archname

       The corresponding command to get the current value of $version is:

           perl -V:version

       To avoid memory leaks, all trailing duplicate entries in @INC are
       removed.

   Deleting directories from @INC
       You should normally only add directories to @INC.  If you need to
       delete directories from @INC take care to only delete those which you
       added yourself or which you are certain are not needed by other modules
       in your script.  Other modules may have added directories which they
       need for correct operation.

       The "no lib" statement deletes all instances of each named directory
       from @INC.

       For each directory in LIST (called $dir here) the lib module also
       checks to see if a directory called $dir/$archname/auto exists.  If so
       the $dir/$archname directory is assumed to be a corresponding
       architecture specific directory and is also deleted from @INC.

   Restoring original @INC
       When the lib module is first loaded it records the current value of
       @INC in an array @lib::ORIG_INC. To restore @INC to that value you can
       say

           @INC = @lib::ORIG_INC;


CAVEATS

       In order to keep lib.pm small and simple, it only works with Unix
       filepaths.  This doesn't mean it only works on Unix, but non-Unix users
       must first translate their file paths to Unix conventions.

           # VMS users wanting to put [.stuff.moo] into
           # their @INC would write
           use lib 'stuff/moo';


NOTES

       In the future, this module will likely use File::Spec for determining
       paths, as it does now for Mac OS (where Unix-style or Mac-style paths
       work, and Unix-style paths are converted properly to Mac-style paths
       before being added to @INC).

       If you try to add a file to @INC as follows:

         use lib 'this_is_a_file.txt';

       "lib" will warn about this. The sole exceptions are files with the
       ".par" extension which are intended to be used as libraries.


SEE ALSO

       FindBin(3) - optional module which deals with paths relative to the 
       source file.

       PAR(3) - optional module which can treat ".par" files as Perl libraries.


AUTHOR

       Tim Bunce, 2nd June 1995.

       "lib" is maintained by the perl5-porters. Please direct any questions
       to the canonical mailing list. Anything that is applicable to the CPAN
       release can be sent to its maintainer, though.

       Maintainer: The Perl5-Porters <perl5-porters@perl.org>

       Maintainer of the CPAN release: Steffen Mueller <smueller@cpan.org>


COPYRIGHT AND LICENSE

       This package has been part of the perl core since perl 5.001.  It has
       been released separately to CPAN so older installations can benefit
       from bug fixes.

       This package has the same copyright and license as the perl core.



perl v5.24.0                      2016-09-12                          lib(3pm)

perl 5.24 - Generated Mon Nov 14 19:20:16 CST 2016
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