6 my $archname = defined($Config{'archname'}) ? $Config{'archname'} : '';
7 my $ver = defined($Config{'version'}) ? $Config{'version'} : '';
8 my @inc_version_list = defined($Config{'inc_version_list'}) ?
9 reverse split / /, $Config{'inc_version_list'} : ();
11 our @ORIG_INC = @INC; # take a handy copy of 'original' value
12 our $VERSION = '0.5564';
18 foreach (reverse @_) {
21 Carp::carp("Empty compile time value given to use lib");
25 Carp::carp("Parameter to use lib must be directory, not file");
28 # Add any previous version directories we found at configure time
29 foreach my $incver (@inc_version_list)
31 unshift(@INC, "$_/$incver") if -d "$_/$incver";
33 # Put a corresponding archlib directory infront of $_ if it
34 # looks like $_ has an archlib directory below it.
35 unshift(@INC, "$_/$ver") if -d "$_/$ver";
36 unshift(@INC, "$_/$ver/$archname") if -d "$_/$ver/$archname";
39 # remove trailing duplicates
40 @INC = grep { ++$names{$_} == 1 } @INC;
51 ++$names{"$_/$archname"} if -d "$_/$archname/auto";
54 # Remove ALL instances of each named directory.
55 @INC = grep { !exists $names{$_} } @INC;
64 lib - manipulate @INC at compile time
74 This is a small simple module which simplifies the manipulation of @INC
77 It is typically used to add extra directories to perl's search path so
78 that later C<use> or C<require> statements will find modules which are
79 not located on perl's default search path.
81 =head2 Adding directories to @INC
83 The parameters to C<use lib> are added to the start of the perl search
88 is I<almost> the same as saying
90 BEGIN { unshift(@INC, LIST) }
92 For each directory in LIST (called $dir here) the lib module also
93 checks to see if a directory called $dir/$archname/auto exists.
94 If so the $dir/$archname directory is assumed to be a corresponding
95 architecture specific directory and is added to @INC in front of $dir.
97 To avoid memory leaks, all trailing duplicate entries in @INC are
100 =head2 Deleting directories from @INC
102 You should normally only add directories to @INC. If you need to
103 delete directories from @INC take care to only delete those which you
104 added yourself or which you are certain are not needed by other modules
105 in your script. Other modules may have added directories which they
106 need for correct operation.
108 The C<no lib> statement deletes all instances of each named directory
111 For each directory in LIST (called $dir here) the lib module also
112 checks to see if a directory called $dir/$archname/auto exists.
113 If so the $dir/$archname directory is assumed to be a corresponding
114 architecture specific directory and is also deleted from @INC.
116 =head2 Restoring original @INC
118 When the lib module is first loaded it records the current value of @INC
119 in an array C<@lib::ORIG_INC>. To restore @INC to that value you
122 @INC = @lib::ORIG_INC;
127 FindBin - optional module which deals with paths relative to the source file.
131 Tim Bunce, 2nd June 1995.