Simple Negative Number Checking Subroutine in Perl

Many times we need to check whether a number is negative or not, here is a very simple subroutine to do that.

Code:

sub isNegative 
 {
     my($checkValue) = @_;
     if(abs($checkValue) != $checkValue) 
     {
         # the value is negative
         return 1;
     } 
     else 
     {
         # number is positive
         return 0;
     }
 }