use Modern::Perl; use Win32::OLE qw/in/; sub memory_usage() { my $objWMI = Win32::OLE->GetObject('winmgmts:\\\\.\\root\\cimv2'); my $processes = $objWMI->ExecQuery("select * from Win32_Process where ProcessId=$$"); foreach my $proc (in($processes)) { return $proc->{WorkingSetSize}; } } sub big_list {return ('blah')x1_000_000}; #Option 1: memory usage 104,443,904 my $size = scalar @{[big_list()]}; #Option 2: memory usage 99,958,784 #my @arr = big_list(); #my $size = scalar @arr; #Option 3: memory usage 108,441,600 #my $size = () = big_list(); #Comparison: memory usage 11,206,656 (results discarded when not used). #big_list(); #my $size = 1; #Can't get what you want, obviously. say "Size: $size"; say 'Memory usage: ', memory_usage(), "\n";