#!/usr/bin/env python
     #
     # Copyright 2007 Doug Hellmann.
     #
     #
     #                         All Rights Reserved
     #
     # Permission to use, copy, modify, and distribute this software and
     # its documentation for any purpose and without fee is hereby
     # granted, provided that the above copyright notice appear in all
     # copies and that both that copyright notice and this permission
     # notice appear in supporting documentation, and that the name of Doug
     # Hellmann not be used in advertising or publicity pertaining to
     # distribution of the software without specific, written prior
     # permission.
     #
     # DOUG HELLMANN DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
     # INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
     # NO EVENT SHALL DOUG HELLMANN BE LIABLE FOR ANY SPECIAL, INDIRECT OR
     # CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
     # OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
     # NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
     # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     #
     
     """Child process in signal example.
     
     """
     
     __module_id__ = "$Id$"
     #end_pymotw_header
     
     import os
     import signal
     import time
     import sys
     
     pid = os.getpid()
     received = False
     
     def signal_usr1(signum, frame):
         "Callback invoked when a signal is received"
         global received
         received = True
         print 'CHILD %6s: Received USR1' % pid
         sys.stdout.flush()
     
     print 'CHILD %6s: Setting up signal handler' % pid
     sys.stdout.flush()
     signal.signal(signal.SIGUSR1, signal_usr1)
     print 'CHILD %6s: Pausing to wait for signal' % pid
     sys.stdout.flush()
     time.sleep(3)
     
     if not received:
         print 'CHILD %6s: Never received signal' % pid