homepage

To add to ben's comment, under py3k the third test hangs, if you pull 
out the basic script code being executed in subprocess:
if 1:
 import sys, os, time, threading
 # a thread, which waits for the main program to terminate
 def joiningfunc(mainthread):
 mainthread.join()
 print('end of thread')
 
if 1:
 main_thread = threading.current_thread()
 def worker():
 childpid = os.fork()
 if childpid != 0:
 os.waitpid(childpid, 0)
 sys.exit(0)
 t = threading.Thread(target=joiningfunc,
 args=(main_thread,))
 print('starting worker')
 t.start()
 print('joining worker')
 t.join() # Should not block: main_thread is already stopped
 w = threading.Thread(target=worker)
 w.start()
You'll note it hangs promptly at the join()