Question

I am using perl v14 on windows. I have 2 simple files:

$SIG{'INT'} = sub {
                print "got SIGINT\n";
                                    #some useful code to be executed
                                    #on reception of signal
};

$SIG{'ALRM'} = sub {
                print "got SIGALRM\n";
};
print "my pid: ",$$,"\n";
while(1)
{
    print "part 1\n";
    sleep(3);
    print "part 2\n\n";
    sleep(3);
}

the above file starts and waits to be killed having given its pid.
The second file simply kills the first perl process using its pid(set manually).

$pid = xxxx;  #this is the manually entered pid for I process
print "will attempt to kill process: $pid\n";
kill INT, $pid;

What I run the first perl script and press Ctrl-C, the handler works as expected but using the second file I can’t get the same result. I have also tried with other signals like ALRM,HUP,TERM,FPE but no success. All I want to do is to execute the code in the signal handler.

I found something called INT2 signal for win32.

Thanks in advance.

Answer 1

Windows does let you use signals only within the same thread. So signaling different processes will not work.

Instead of signals you could use other methods of interprocess communication like sockets, pipes or files.

From perlwin32:

Signal handling may not behave as on Unix platforms (where it doesn’t
exactly “behave”, either :). For instance, calling die() or exit()
from signal handlers will cause an exception, since most
implementations of signal() on Windows are severely crippled. Thus,
signals may work only for simple things like setting a flag variable
in the handler. Using signals under this port should currently be
considered unsupported.