Question

I am writing a function in perl which will kill a process given its PID.

sub ShutPidForWindows()
{
    require Win32::Process;
    $PID = 1234;
    $count = 0;
    $ReturnStatus = 0;
    $ExitCode = 0 ;

    if ($PID == 0)
    {
        return ($ReturnStatus);
    }

    Win32::Process::KillProcess($PID, $ExitCode);
    print "PID = ".$PID."\n";
    print "Return Code = ".$ExitCode."\n";

    if ($ExitCode)
    {
        $ReturnStatus = 1;
    }
    else
    {
        $ReturnStatus = 2;
    }
    return ($ReturnStatus);
}

when this function is executed it always returns 2. Even though the process 1234 does not exists.

The o/p I get is:

PID = 1234
Return Code = 0

Perl Doc says that ExitCode will be populated by the exit code returned by the process. Then ExitCode should be 1.

Am I doing anything wrong?

Answer 1

The problem is that you are using require instead of use to load the module. Sometimes this is OK, but you should always follow the examples in the module’s documentation.

You must also always use strict and use warnings at the top of every Perl program you write. This will make it necessary to declare all of your variables, which should be done as close as possible to their first point of use. These measures will reveal many errors that you may otherwise overlook, and is especially important when you are asking others for help with your code.