1lib(3pm)               Perl Programmers Reference Guide               lib(3pm)
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NAME

6       lib - manipulate @INC at compile time
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SYNOPSIS

9           use lib LIST;
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11           no lib LIST;
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DESCRIPTION

14       This is a small simple module which simplifies the manipulation of @INC
15       at compile time.
16
17       It is typically used to add extra directories to perl's search path so
18       that later "use" or "require" statements will find modules which are
19       not located on perl's default search path.
20
21   Adding directories to @INC
22       The parameters to "use lib" are added to the start of the perl search
23       path. Saying
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25           use lib LIST;
26
27       is almost the same as saying
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29           BEGIN { unshift(@INC, LIST) }
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31       For each directory in LIST (called $dir here) the lib module also
32       checks to see if a directory called $dir/$archname/auto exists.  If so
33       the $dir/$archname directory is assumed to be a corresponding
34       architecture specific directory and is added to @INC in front of $dir.
35       lib.pm also checks if directories called $dir/$version and
36       $dir/$version/$archname exist and adds these directories to @INC.
37
38       The current value of $archname can be found with this command:
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40           perl -V:archname
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42       The corresponding command to get the current value of $version is:
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44           perl -V:version
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46       To avoid memory leaks, all trailing duplicate entries in @INC are
47       removed.
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49   Deleting directories from @INC
50       You should normally only add directories to @INC.  If you need to
51       delete directories from @INC take care to only delete those which you
52       added yourself or which you are certain are not needed by other modules
53       in your script.  Other modules may have added directories which they
54       need for correct operation.
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56       The "no lib" statement deletes all instances of each named directory
57       from @INC.
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59       For each directory in LIST (called $dir here) the lib module also
60       checks to see if a directory called $dir/$archname/auto exists.  If so
61       the $dir/$archname directory is assumed to be a corresponding
62       architecture specific directory and is also deleted from @INC. lib.pm
63       also checks if directories called $dir/$version and
64       $dir/$version/$archname exist and deletes these directories from @INC.
65
66   Restoring original @INC
67       When the lib module is first loaded it records the current value of
68       @INC in an array @lib::ORIG_INC. To restore @INC to that value you can
69       say
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71           @INC = @lib::ORIG_INC;
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CAVEATS

74       In order to keep lib.pm small and simple, it only works with Unix
75       filepaths.  This doesn't mean it only works on Unix, but non-Unix users
76       must first translate their file paths to Unix conventions.
77
78           # VMS users wanting to put [.stuff.moo] into
79           # their @INC would write
80           use lib 'stuff/moo';
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NOTES

83       In the future, this module will likely use File::Spec for determining
84       paths, as it does now for Mac OS (where Unix-style or Mac-style paths
85       work, and Unix-style paths are converted properly to Mac-style paths
86       before being added to @INC).
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88       If you try to add a file to @INC as follows:
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90         use lib 'this_is_a_file.txt';
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92       "lib" will warn about this. The sole exceptions are files with the
93       ".par" extension which are intended to be used as libraries.
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SEE ALSO

96       FindBin - optional module which deals with paths relative to the source
97       file.
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99       PAR - optional module which can treat ".par" files as Perl libraries.
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AUTHOR

102       Tim Bunce, 2nd June 1995.
103
104       "lib" is maintained by the perl5-porters. Please direct any questions
105       to the canonical mailing list. Anything that is applicable to the CPAN
106       release can be sent to its maintainer, though.
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108       Maintainer: The Perl5-Porters <perl5-porters@perl.org>
109
110       Maintainer of the CPAN release: Steffen Mueller <smueller@cpan.org>
111

113       This package has been part of the perl core since perl 5.001.  It has
114       been released separately to CPAN so older installations can benefit
115       from bug fixes.
116
117       This package has the same copyright and license as the perl core.
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121perl v5.34.0                      2021-10-18                          lib(3pm)
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