#! perl -slw
use strict;

$|++;

my $extApp = q[ perl -lwe"$|++; print $_ and sleep 1 for 1 .. 10" ];

for my $timeout ( map $_*2, 4,5,6 ) {
    my @results = timedCommand( $extApp, $timeout );
    if( @results ) {
        print "Command returned\n", join '', @results;
    }
    else {
        print "Command timed out after $timeout seconds";
    }
}


sub timedCommand {
    use threads;
    use threads::shared;
    my( $cmd, $timeout ) = @_;

    my @results :shared;
    my $pid :shared;

    async {
        $pid = open my $fh, "$cmd |" or die "$!, $^E";
        @results = <$fh>;
    }->detach;

    kill 0, $pid while sleep 1 and $timeout--;
    kill 3, $pid and return if $timeout;
    return @results;
}
__END__
c:\test>junk6
Command timed out after 8 seconds
Command returned
1
2
3
4
5
6
7
8
9
10

Command returned
1
2
3
4
5
6
7
8
9
10