- NAME
- SYNOPSIS
- DESCRIPTION
  - ADDING DIRECTORIES TO @INC
  - DELETING DIRECTORIES FROM @INC
  - RESTORING ORIGINAL @INC
- SEE ALSO
- AUTHOR

# 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.

If LIST includes both `$dir` and $dir/$archname then $dir/$archname will be added to @INC twice (if $dir/$archname/auto exists).

## 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.

By default the `no lib` statement deletes the first instance of each named directory from @INC. To delete multiple instances of the same name from @INC you can specify the name multiple times.

To delete all instances of all the specified names from @INC you can specify ':ALL' as the first parameter of `no lib`. For example:

        no lib qw(:ALL .);

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.

If LIST includes both `$dir` and $dir/$archname then $dir/$archname will be deleted from @INC twice (if $dir/$archname/auto exists).

## 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;

# SEE ALSO

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

# AUTHOR

Tim Bunce, 2nd June 1995.