in reply to Re^4: Reliably parsing an integer
in thread Reliably parsing an integer

Create the largest integer number that the current Perl interpreter supports.

If you aren't picking a specific maximum number but just want to allow whatever the running perl does then you just need a function like this valid_int here:

use strict; use warnings; use Test::More tests => 5; ok valid_int ('18446744073709551614'), '1 under max int'; ok valid_int ('18446744073709551615'), 'exactly max int'; ok ! valid_int ('18446744073709551616'), '1 over max int'; ok ! valid_int ('foo'), 'NaN'; ok ! valid_int ('1.3'), 'float'; sub valid_int { my $num = shift; return unless $num =~ /^\d+$/a; return int $num eq $num; }

The hard-coded values are just to test because I am on a 64-bit perl, adjust them to your own testing environment as appropriate.