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 \f(CW@INC\fP

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
.

The current value of 

$archname
can be found with this command: 


    perl -V:archname

To avoid memory leaks, all trailing duplicate entries in 

@INC
are removed.

Deleting directories from \f(CW@INC\fP

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 \f(CW@INC\fP

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
).

SEE ALSO

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

AUTHOR

Tim Bunce, 2nd June 1995.

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