CODEWITHSUNDEEP
pythonwindowsblockingcommand-line-interfaceraw-input
schluchc
schluchc

Reputation: 4174

Python: How to quit CLI when stuck in blocking raw_input?

I have a GUI program which should also be controllable via CLI (for monitoring). The CLI is implemented in a while loop using raw_input. If I quit the program via a GUI close button, it hangs in raw_input and does not quit until it gets an input.

How can I immediately abort raw_input without entering an input?

I run it on WinXP but I want it to be platform independent, it should also work within Eclipse since it is a developer tool. Python version is 2.6.

I searched stackoverflow for hours and I know there are many answers to that topic, but is there really no platform independent solution to have a non-blocking CLI reader?

If not, what would be the best way to overcome this problem?

Thanks

Upvotes: 2

Views: 2795

Answers (2)

Martin Trigaux
Martin Trigaux

Reputation: 5411

That's not maybe the best solution but you could use the thread module which has a function thread.interrupt_main(). So can run two thread : one with your raw_input method and one which can give the interruption signal. The upper level thread raise a KeyboardInterrupt exception.

import thread
import time

def main():
    try:
        m = thread.start_new_thread(killable_input, tuple())
        while 1:
            time.sleep(0.1) 
    except KeyboardInterrupt:
        print "exception" 

def killable_input():
    w = thread.start_new_thread(normal_input, tuple())
    i = thread.start_new_thread(wait_sometime, tuple())


def normal_input():
    s = raw_input("input:")


def wait_sometime():
    time.sleep(4) # or any other condition to kill the thread
    print "too slow, killing imput"
    thread.interrupt_main()

if __name__ == '__main__':
    main()

Upvotes: 2

moinudin
moinudin

Reputation: 138487

Depending on what GUI toolkit you're using, find a way to hook up an event listener to the close window action and make it call win32api.TerminateProcess(-1, 0).

For reference, on Linux calling sys.exit() works.

Upvotes: 1

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