Chris Angelico <ros...@gmail.com>:
> But also, this honestly isn't as big an issue as you might think. If
> the user thinks a program has been running for too long, s/he can hit
> Ctrl-C. Voila! Signal is sent, which aborts a socket read,
Well, no, it doesn't. First run:
========================================================================
nc -l -p 12345
========================================================================
in one window. Then, execute this program in another one:
========================================================================
import threading, socket
def f():
s = socket.socket()
try:
s.connect(("localhost4", 12345))
s.recv(1000)
finally:
s.close()
t = threading.Thread(target=f)
t.start()
t.join()
========================================================================
After you hit Ctrl-C once (under Linux), you get this trace:
========================================================================
Traceback (most recent call last):
File "test.py", line 13, in <module>
t.join()
File "/usr/lib64/python3.5/threading.py", line 1054, in join
self._wait_for_tstate_lock()
File "/usr/lib64/python3.5/threading.py", line 1070, in _wait_for_tstate_lock
elif lock.acquire(block, timeout):
KeyboardInterrupt
========================================================================
The program hangs, though, and "nc" doesn't terminate indicating that
the socket hasn't closed.
Then, press Ctrl-C again to get:
========================================================================
Exception ignored in: <module 'threading' from
'/usr/lib64/python3.5/threading.py'>
Traceback (most recent call last):
File "/usr/lib64/python3.5/threading.py", line 1288, in _shutdown
t.join()
File "/usr/lib64/python3.5/threading.py", line 1054, in join
self._wait_for_tstate_lock()
File "/usr/lib64/python3.5/threading.py", line 1070, in _wait_for_tstate_lock
elif lock.acquire(block, timeout):
KeyboardInterrupt
========================================================================
and the program terminates.
Marko
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