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author | Victor Stinner <victor.stinner@gmail.com> | 2014-04-07 09:18:06 (GMT) |
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committer | Victor Stinner <victor.stinner@gmail.com> | 2014-04-07 09:18:06 (GMT) |
commit | 4bd652a276c575de476d634da8cc4f95815721e9 (patch) | |
tree | 797d279d672c84bc2840d2db6fd75ddd3d5e0316 /Lib/asyncio/tasks.py | |
parent | 6d6ec25e043230a8b97b2773f4b50c1495393b0d (diff) | |
download | cpython-4bd652a276c575de476d634da8cc4f95815721e9.zip cpython-4bd652a276c575de476d634da8cc4f95815721e9.tar.gz cpython-4bd652a276c575de476d634da8cc4f95815721e9.tar.bz2 |
asyncio: Document Task.cancel() properly.
Diffstat (limited to 'Lib/asyncio/tasks.py')
-rw-r--r-- | Lib/asyncio/tasks.py | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py index 0967e7e..153f731 100644 --- a/Lib/asyncio/tasks.py +++ b/Lib/asyncio/tasks.py @@ -250,6 +250,25 @@ class Task(futures.Future): print(line, file=file, end='') def cancel(self): + """Request that a task to cancel itself. + + This arranges for a CancellationError to be thrown into the + wrapped coroutine on the next cycle through the event loop. + The coroutine then has a chance to clean up or even deny + the request using try/except/finally. + + Contrary to Future.cancel(), this does not guarantee that the + task will be cancelled: the exception might be caught and + acted upon, delaying cancellation of the task or preventing it + completely. The task may also return a value or raise a + different exception. + + Immediately after this method is called, Task.cancelled() will + not return True (unless the task was already cancelled). A + task will be marked as cancelled when the wrapped coroutine + terminates with a CancelledError exception (even if cancel() + was not called). + """ if self.done(): return False if self._fut_waiter is not None: |