gh-131803: Clarify that you must register signal handlers for set_wakeup_fd (#131859)

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Jeremy Fleischman 2025-04-14 09:46:11 -07:00 committed by GitHub
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@ -510,10 +510,12 @@ The :mod:`signal` module defines the following functions:
.. function:: set_wakeup_fd(fd, *, warn_on_full_buffer=True)
Set the wakeup file descriptor to *fd*. When a signal is received, the
signal number is written as a single byte into the fd. This can be used by
a library to wakeup a poll or select call, allowing the signal to be fully
processed.
Set the wakeup file descriptor to *fd*. When a signal your program has
registered a signal handler for is received, the signal number is written as
a single byte into the fd. If you haven't registered a signal handler for
the signals you care about, then nothing will be written to the wakeup fd.
This can be used by a library to wakeup a poll or select call, allowing the
signal to be fully processed.
The old wakeup fd is returned (or -1 if file descriptor wakeup was not
enabled). If *fd* is -1, file descriptor wakeup is disabled.