sub foo {
    #...
    return { errno => 0, errmess => $msg };
}

my $error = foo();
print $error->{errno}, $error->{errmess};

##</code><code>##

sub foo {
    #...
    return ( 0, $msg );
}

my ( $errno, $errmess ) = foo();

##</code><code>##

if ($var = 0) {

##</code><code>##

use strict;
use warnings;