use warnings;
use strict;
use feature 'say';

say 'foobar';
warn 'this is a warning';

##</code><code>##

use warnings;
use strict;
use IPC::Open3;
use feature qw(say);

my ( $wtr, $rdr, $err );
my $pid = open3( $wtr, $rdr, $err, 'perl', 'dummy.pl' );

while (<$rdr>) {

    print $_;

}

while (<$err>) {

    print $_;

}

close($err);
close($rdr);
close($wtr);

waitpid( $pid, 0 );

##</code><code>##

c:\Temp>teste.pl
this is a warning at dummy.pl line 7.
foobar
Use of uninitialized value $err in <HANDLE> at C:\Temp\teste.pl line 15.
readline() on unopened filehandle at C:\Temp\teste.pl line 15.

##</code><code>##

This is perl 5, version 16, subversion 3 (v5.16.3) built for MSWin32-x86-multi-thread