Capturing an external program return code

[Vladimir Lemberg]

Hi All,
 
My script is executing external program, which returns code i.e 0, -1, -2, -3 
etc
In case of error, I need to create log file according to error code.
 
For example code -3 means missing input file
 
use strict;
use warnings;
use Win32;
 
system ( "$program -f $program.cfg" );
if ($? == -3) {
   
   print error message to log file    

}

This is not working. Nothing is printing to the log file when I'm simulating -3 
code. If I print $?, it shown 65280.

I'll appreciate any help to solve this problem.

Thanks,
Vladimir