lib(3p) Perl Programmers Reference Guide lib(3p) #
lib(3p) Perl Programmers Reference Guide lib(3p)
NNAAMMEE #
lib - manipulate @INC at compile time
SSYYNNOOPPSSIISS #
use lib LIST;
no lib LIST;
DDEESSCCRRIIPPTTIIOONN #
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.
AAddddiinngg ddiirreeccttoorriieess ttoo @@IINNCC The parameters to “use lib” are added to the start of the perl search path. Saying
use lib LIST;
is _a_l_m_o_s_t 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.
DDeelleettiinngg ddiirreeccttoorriieess ffrroomm @@IINNCC 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. lib.pm also checks if
directories called $dir/$version and $dir/$version/$archname exist and
deletes these directories from @INC.
RReessttoorriinngg oorriiggiinnaall @@IINNCC 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;
CCAAVVEEAATTSS #
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';
NNOOTTEESS #
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.
SSEEEE AALLSSOO #
FindBin - optional module which deals with paths relative to the source
file.
PAR - optional module which can treat ".par" files as Perl libraries.
AAUUTTHHOORR #
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>
CCOOPPYYRRIIGGHHTT AANNDD LLIICCEENNSSEE #
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 v5.36.3 2024-03-20 lib(3p)