As far as Unix vs windows, ideally both. Ultimately there are 4 target OS's for this program to run on: SUSE 11, RHEL 6, Win Server 2008, Win Server 2008R2

I am developing on a client box running OpenSUSE 11.4, but the final code will live on servers.

I can of course make code changes to port between Unix and Windows, but I would prefer to keep this at a minimum since I will also have a significant task to port the test scripts to run in windows.

I suppose one approach would be to capture the process ID returned from openN or runN, and pass that to a watchdog thread with seconds since epoch. The watchdog thread would watch the time on each process id, and kill the system process rather then the perl thread. Once the process is killed, the handlers will cause the while loop to exit and the thread to continue from the hang. Somewhat like:

$pid = open2($chldout, $chldin, $cmdstring);
while(<$chldout>){
   #process script output strings
   $mytime=time;
   watchdogQ->enqueue("$pid $mytime");  #"pet the watchdog"
}
   #use $? to determine timeout case or not
[download]

is openN / runN implemented by launching a separate process from my main program, or a thread like implemented? is this approach thread safe?

This is a somwhat simpler approach and is thread-safe:

#! perl -sw
use strict;
use threads;
use threads::shared;

our $T //= 5;

my $pid :shared;
my( $t ) = threads->create(
    sub{
        my @input;
        $pid = open my $in, '-|', 
            q[ perl -wle"$|++; print() and sleep 1 for 1.. 5" ]
            or die $!;
        push @input, $_ while <$in>;
        return @input;
    }
);

sleep $T;
kill 21, $pid;

my @input = $t->join;

print for @input;

__END__

c:\test>junk82 -T=4
Terminating on signal SIGBREAK(21)
1
2
3
4

c:\test>junk82 -T=5
Terminating on signal SIGBREAK(21)
1
2
3
4
5

c:\test>junk82 -T=6
1
2
3
4
5
[download]

It does have a caveat that you may loose some output buffered by the child process, but is otherwise quite reliable and should work wherever threads do.

---

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