How to start a subprocess, display its output in a graphical interface and allow its completion?

Question

I am trying to write an application that executes subprocesses and (among other things) displays their output in a graphical interface and allows the user to click a button to cancel them. I start such processes as follows:

queue = Queue.Queue(500)
process = subprocess.Popen(
    command,
    stdout=subprocess.PIPE,
    stderr=subprocess.STDOUT)
iothread = threading.Thread(
    target=simple_io_thread,
    args=(process.stdout, queue))
iothread.daemon=True
iothread.start()

where simple_io_thread is defined as follows:

def simple_io_thread(pipe, queue):
    while True:
        line = pipe.readline()
        queue.put(line, block=True)
        if line=="":
            break

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process.stdout.close()

:

IOError: close() called during concurrent operation on the same file object.

... . :

os.close(process.stdout.fileno())

:

close failed in file object destructor: IOError: [Errno 9] Bad file descriptor

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Answer 1

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process.poll() ; , (.. process.poll() == None). if line == "": break.

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IOError: close() called during concurrent operation on the same file object..

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def io_thread(subprocess,logfile,lock):
    for line in subprocess.stdout:
        lock.acquire()
        print line,
        lock.release()
        logfile.write( line )

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Answer 2

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my_thread.join()
print my_thread.is_alive()
my_popen.communicate()

Answer 3

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Answer 4

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• read read simple_io_thread .

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queue = Queue.Queue(500)
r, w = os.pipe()
process = subprocess.Popen(
    command,
    stdout=w,
    stderr=subprocess.STDOUT)
iothread = threading.Thread(
    target=simple_io_thread,
    args=(os.fdopen(r), queue))
iothread.daemon=True
iothread.start()

os.close(w)

You can close the phone and it iothreadwill be disconnected without any exceptions.