Apparently today is "See how many times you can recommend IPC::Run" day. (There's also alarm and more info in perlipc . . .)

That does the time limit part, but I don't know how to notify other programs of a timeout - perhaps trapping some signals might help.

You can also look on cpan for ipc, run and system, maybe one of the great many modules does that job for you already.

You can try using something like a named pipe.

Edit: when I've seen named pipes used as a timing mechanism, it was when there was a process that could run to completion in X seconds or then be killed. You would set up two coprocesses in a shell, one monitoring the other. When time was up, one process would kill the other if it had not completed and sent the completion message through the pipe. I'm not sure if the questioner is wanting a run or die scenario.

BSD::Resource RLIMIT_CPU apparently does not work in linux:

h@e12a8t:~$ perl -le 'use BSD::Resource; print for RLIMIT_CPU, q(--), 
+getrlimit(RLIMIT_CPU), q(--), getrusage(), q(--), setrlimit(RLIMIT_CP
+U, 10, 20), qq(--), getrlimit(RLIMIT_CPU), q(--); $SIG{XCPU} = sub { 
+print "LIMIT" }; (sleep 1), printf "$_: %s %s\n", getrusage() for 1 .
+. 100;'
0
--
-1
-1
--
0.024001
0.008
0
0
0
0
685
0
0
0
0
0
0
0
1
0
--
1
--
10
20
--
1: 0.024001 0.008
2: 0.024001 0.008
3: 0.024001 0.008
4: 0.024001 0.008
5: 0.024001 0.008
6: 0.024001 0.008
7: 0.024001 0.008
8: 0.024001 0.008
9: 0.024001 0.008
10: 0.024001 0.008
11: 0.024001 0.008
[download]

goes all the way up to 100.

A well, I guess it just limits CPU time and not run time - perhaps not what the OP wanted. Your script doesn't really use much CPU time (less than 0.03 on my machine), so it won't get killed.

That's fine for my applications, but perhaps not so good in the general application.

   eval {
        local $SIG{ALRM} = sub { die "alarm clock restart" };
        alarm 10;
        flock(FH, 2);   # blocking write lock
        alarm 0;
    };
    if ($@ and $@ !~ /alarm clock restart/) { die }
[download]

#!/usr/bin/perl 
use strict;
use warnings;

# by edan of perlmonks, works great
spawn(5, "xterm");
spawn(5, "xterm");
spawn(5, "xterm");
spawn(5, "xterm");

print "Hit enter to quit\n";
<>;


sub spawn
{
  my ($timeout, @cmd) = @_;
  defined( my $child_pid = fork ) or die "fork: $!";

   if ($child_pid)
      {
       # parent
         eval
             {
              local $SIG{ALRM} = sub { timeout($child_pid); };
              alarm $timeout;
              waitpid $child_pid, 0;
              alarm 0;
      };

       if ($@){print "oops: $@";}

   }else{
     # child
     exec @cmd or die "exec: $!";
    }
}

sub timeout
{
  my ($pid) = @_;
  kill 'TERM' => $pid;
  waitpid $pid, 0;
  die "reaped $pid\n";
}
[download]

Fork. The child execute the system call, the parent sleeps the desired time and then send the message.

If the child terminates before the timeout, wakes the parent and the message is not sent.

Could it work?