Python 3.3+Linux · macOSsignalfunction

signal.sigwait()

masks and waiting

Waits for one of the given signals, takes it off the pending set and returns its number; no handler is called. Unix only (Linux, macOS).

Syntax

signum = signal.sigwait(sigset)

It only works reliably when the awaited signals are blocked with pthread_sigmask beforehand: otherwise the signal goes to the handler (or kills the process) before sigwait sees it. There is no timeout — use sigtimedwait for a bounded wait (it is missing on macOS). The classic pattern is a dedicated thread calling sigwait in a loop and handling signals synchronously.

Examples

import signal
old = signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGUSR1})  # сначала блок
signal.raise_signal(signal.SIGUSR1)
print(signal.sigwait({signal.SIGUSR1}).name)  # → SIGUSR1 — сразу, сигнал уже ждал
signal.pthread_sigmask(signal.SIG_SETMASK, old)

See also

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