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Diffstat (limited to 'demo3/one_shot_signal.py')
-rw-r--r-- | demo3/one_shot_signal.py | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/demo3/one_shot_signal.py b/demo3/one_shot_signal.py new file mode 100644 index 0000000..23efe08 --- /dev/null +++ b/demo3/one_shot_signal.py @@ -0,0 +1,45 @@ +# Python modules +import time +import signal + +# 3rd party modules +import posix_ipc + +# Utils for this demo +import utils + + +MY_SIGNAL = signal.SIGUSR1 + + +def handle_signal(signal_number, stack_frame): + message, priority = mq.receive() + + print ("Ding! Message with priority %d received: %s" % (priority, message)) + + + +# Create the message queue. +mq = posix_ipc.MessageQueue(utils.QUEUE_NAME, posix_ipc.O_CREX) + +# Request notifications +mq.request_notification(MY_SIGNAL) + +# Register my signal handler +signal.signal(MY_SIGNAL, handle_signal) + +# Get user input and send it to the queue. +print ("Enter a message:") +mq.send(utils.get_input()) + +# The signal fires almost instantly, but if I don't pause at least +# briefly then the main thread may exit before the notification fires. +print ("Sleeping for one second to allow the notification to happen.") +time.sleep(1) + +print ("Destroying the message queue.") +mq.close() +# I could call simply mq.unlink() here but in order to demonstrate +# unlinking at the module level I'll do it that way. +posix_ipc.unlink_message_queue(utils.QUEUE_NAME) + |