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+package lib;
+
+use vars qw(@ORIG_INC);
+use Config;
+
+my $archname = $Config{'archname'};
+
+@ORIG_INC = @INC; # take a handy copy of 'original' value
+
+
+sub import {
+ shift;
+ foreach (reverse @_) {
+ ## Ignore this if not defined.
+ next unless defined($_);
+ if ($_ eq '') {
+ require Carp;
+ Carp::carp("Empty compile time value given to use lib");
+ # at foo.pl line ...
+ }
+ if (-e && ! -d _) {
+ require Carp;
+ Carp::carp("Parameter to use lib must be directory, not file");
+ }
+ unshift(@INC, $_);
+ # Put a corresponding archlib directory infront of $_ if it
+ # looks like $_ has an archlib directory below it.
+ if (-d "$_/$archname") {
+ unshift(@INC, "$_/$archname") if -d "$_/$archname/auto";
+ unshift(@INC, "$_/$archname/$]") if -d "$_/$archname/$]/auto";
+ }
+ }
+}
+
+
+sub unimport {
+ shift;
+ my $mode = shift if $_[0] =~ m/^:[A-Z]+/;
+
+ my %names;
+ foreach(@_) {
+ ++$names{$_};
+ ++$names{"$_/$archname"} if -d "$_/$archname/auto";
+ }
+
+ if ($mode and $mode eq ':ALL') {
+ # Remove ALL instances of each named directory.
+ @INC = grep { !exists $names{$_} } @INC;
+ } else {
+ # Remove INITIAL instance(s) of each named directory.
+ @INC = grep { --$names{$_} < 0 } @INC;
+ }
+}
+
+1;
+__END__
+
+=head1 NAME
+
+lib - manipulate @INC at compile time
+
+=head1 SYNOPSIS
+
+ use lib LIST;
+
+ no lib LIST;
+
+=head1 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 C<use> or C<require> statements will find modules which are
+not located on perl's default search path.
+
+=head2 ADDING DIRECTORIES TO @INC
+
+The parameters to C<use lib> are added to the start of the perl search
+path. Saying
+
+ use lib LIST;
+
+is I<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).
+
+=head2 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 C<no lib> statement deletes the I<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 I<all> instances of I<all> the specified names from @INC you can
+specify ':ALL' as the first parameter of C<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).
+
+=head2 RESTORING ORIGINAL @INC
+
+When the lib module is first loaded it records the current value of @INC
+in an array C<@lib::ORIG_INC>. To restore @INC to that value you
+can say
+
+ @INC = @lib::ORIG_INC;
+
+
+=head1 SEE ALSO
+
+FindBin - optional module which deals with paths relative to the source file.
+
+=head1 AUTHOR
+
+Tim Bunce, 2nd June 1995.
+
+=cut
+
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