package vars;=head1 NAMEvars - Perl pragma to predeclare global variable names=head1 SYNOPSIS    use vars qw($frob @mung %seen);=head1 DESCRIPTIONThis will predeclare all the variables whose names are in the list, allowing you to use them under "use strict", anddisabling any typo warnings.See L<perlmod/Pragmatic Modules>.=cutrequire 5.000;use Carp;sub import {    my $callpack = caller;    my ($pack, @imports, $sym, $ch) = @_;    foreach $sym (@imports) {	croak "Can't declare another package's variables" if $sym =~ /::/;        ($ch, $sym) = unpack('a1a*', $sym);        *{"${callpack}::$sym"} =          (  $ch eq "\$" ? \$   {"${callpack}::$sym"}           : $ch eq "\@" ? \@   {"${callpack}::$sym"}           : $ch eq "\%" ? \%   {"${callpack}::$sym"}           : $ch eq "\*" ? \*   {"${callpack}::$sym"}           : $ch eq "\&" ? \&   {"${callpack}::$sym"}           : croak "'$ch$sym' is not a valid variable name\n");    }};1;