multithreading - Python multiprocessing and sockets not being closed -

i'm experiencing odd behaviour when using multiprocessing , socket on python. i'm dealing piece of code similar 1 i'm posting below (i've simplified things lot trying naive).

the code spawns 3 processes: 1 process nothing, process launches third one, listening on socket. if terminate "listener" process, socket still remains open (i can see there netstat).

• if remove (or stop) "donothing" process, works.
• if switch threading.thread, works, but
• if leave donothing process , switch server , launcher threading.thread, problem persists.

does have hint why socket still opened? there problem dealing multiprocessing , sockets?

i'm using python 2.6.6 running on linux.

thank much, alvaro.

import time multiprocessing import process, event  import socket  class server(process):     def __init__(self, port):         super(server, self).__init__()          self.s = socket.socket(socket.af_inet, socket.sock_stream)         self.s.bind(("127.0.0.1",port))         self.s.listen(1)         self.s.settimeout(10)         self.is_stop = event()         self.is_stop.clear()      def run(self):         while not self.is_stop.is_set():             print "server: running (pid %s)" % self.pid              time.sleep(1)         print "server: exiting"      def stop(self):         self.is_stop.set()         self.s.close()  class launcher(process):     def __init__(self):         super(launcher, self).__init__()         self.srv = server(9999)         self.srv.start()      def run(self):         print "launcher pid %s" % self.pid         while true:             time.sleep(1)      def stop(self):         print "launcher: i'm stopping server"         self.srv.stop()         self.srv.terminate()         self.srv.join()         print "launcher: server stopped"  class donothing(process):     def __init__(self):                         super(donothing, self).__init__()      def run(self):         while true:             time.sleep(1)   l = launcher() l.start()  dn = donothing() dn.start()  time.sleep(2)  print " stop launcher " l.stop()  while true:     time.sleep(1) 

edit:

relevant netstat -lnp output:

tcp        0      0 127.0.0.1:9999          0.0.0.0:*               listen      7183/python 

i've noticed pid shown in netstat changes parent process (when process server running) launcher's 1 (when server stopped).

to fix immediate problem (of socket not shutting down), add self.s.shutdown(socket.shut_rdwr) server.stop method:

def stop(self):     self.is_stop.set()     self.s.shutdown(socket.shut_rdwr)      self.s.close()