From 939476bbbb57ec3348c60df7c8f67c92038c8c89 Mon Sep 17 00:00:00 2001 From: Jeremy Fleischman Date: Mon, 14 Apr 2025 09:46:11 -0700 Subject: [PATCH] gh-131803: Clarify that you must register signal handlers for set_wakeup_fd (#131859) --- Doc/library/signal.rst | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/Doc/library/signal.rst b/Doc/library/signal.rst index 17fcb2b3707..c28841dbb8c 100644 --- a/Doc/library/signal.rst +++ b/Doc/library/signal.rst @@ -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.