signal_threads.py

#!/usr/bin/env python3
# encoding: utf-8
#
# Copyright (c) 2008 Doug Hellmann All rights reserved.
#
"""
"""


#end_pymotw_header
import signal
import threading
import os
import time


def signal_handler(num, stack):
    print('Received signal {} in {}'.format(
        num, threading.currentThread().name))


signal.signal(signal.SIGUSR1, signal_handler)


def wait_for_signal():
    print('Waiting for signal in',
          threading.currentThread().name)
    signal.pause()
    print('Done waiting')


# Start a thread that will not receive the signal
receiver = threading.Thread(
    target=wait_for_signal,
    name='receiver',
)
receiver.start()
time.sleep(0.1)


def send_signal():
    print('Sending signal in', threading.currentThread().name)
    os.kill(os.getpid(), signal.SIGUSR1)


sender = threading.Thread(target=send_signal, name='sender')
sender.start()
sender.join()

# Wait for the thread to see the signal (not going to happen!)
print('Waiting for', receiver.name)
signal.alarm(2)
receiver.join()