#!/usr/bin/perl                                                                                                                                                                                                    
 
use strict;
 
my %hash = (
            foo => scalar(mysub()),
            );
 
sub mysub {
    print "wantarray(): " . wantarray() . "\n";
    return ( 'bar', 'baz', 'blah' );
}
 
use Data::Dumper;
print Dumper(\%hash);