c:\@Work\Perl\monks>perl -le
"use strict;
 use warnings;
 ;;
 no warnings 'numeric';
 print 'numeric warning DISabled';
 ;;
 print q{'abc' }, isNumber('abc');
 print q{'123' }, isNumber('123');
 print q{123 },   isNumber(123);
 ;;
 sub isNumber
 {
   @_ or return 0;
   my $N = shift;
   defined $N or return 0;
   my $R = 1;
   {
     local $SIG{__WARN__} = sub { $R = 0; };
     $N = int($N);
   }
   return $R;
 }
"
numeric warning DISabled
'abc' 1
'123' 1
123 1