Wow. Thanks. But... I've checked threads module documentation before post here! Here is it:

$thread = threads->create(function, LIST)

This will create a new thread with the entry point function and give it LIST as parameters. It will return the corresponding threads object. The new() method is an alias for create().

$thread->join

This will wait for the corresponding thread to join. When the thread finishes, join() will return the return values of the entry point function. If the thread has been detached, an error will be thrown. If the program exits without all other threads having been either joined or detached, then a warning will be issued. (A program exits either because one of its threads explicitly calls exit(), or in the case of the main thread, reaches the end of the main program file.)

I'm using perl 5.8.0 and this is text from `perldoc threads`. So, where you find your version of this documentation?