All functions that are capable of creating filehandles (open(), opendir(), pipe(), socketpair(), sysopen(), socket(), and accept()) automatically create an anonymous filehandle if the handle passed to them is an uninitialized scalar variable. This allows the constructs such as "open(my $fh, ...)" and "open(local $fh,...)" to be used to create filehandles that will conveniently be closed automatically when the scope ends, provided there are no other references to them. This largely eliminates the need for typeglobs when opening filehandles that must be passed around, as in the following example:

           sub myopen {
               open my $fh, "@_"
                    or die "Can't open '@_': $!";
               return $fh;
           }

           {
               my $f = myopen("</etc/motd");
               print <$f>;
               # $f implicitly closed here
           }
[download]

Hope this helps...

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
[download]

#!/usr/bin/perl -w

use IO::File;
use strict;

my( %files, $ele1, $ele2, $ele3, $id, $fh );

while( <> ) {
        ($ele1, $ele2, $ele3, $id ) = split;
        $files{$id} = $fh = $files{$id} || openup( $id );
        print $fh $id, ":\t", $ele1, "\t", $ele2, "\t", $ele3, "\n";
}

sub openup {
        my( $filename ) = shift;
        my $fh = IO::File->new( $filename, "w" ) ||
                die "unable to open $filename ($!)\n";
        return $fh;
}
[download]

-derby