#!/usr/bin/perl -w
use threads;
use threads::shared;

my $status : shared;

my $thr_work = threads->create(
    sub {

        # do some work. 
        lock $status;
        return if $status;
        $status = "done";
        cond_signal $status;
        return @whatever;
    }
);

threads->create(
    sub {
        sleep 300;
        lock $status;
        return if $status;
        $status = "timed_out";
        cond_signal $status;
    }
)->detach;

{
    lock $status;
    cond_wait $status until $status;
    if ( $status eq "done" ) {
        my @results = $thr_work->join;

        # process @results. 
    }
    else {
        print "Timed out\n";
        $thr_work->detatch;
    }
}