signal.set_wakeup_fd()

signal.set_wakeup_fd(fd)

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.

The old wakeup fd is returned. fd must be non-blocking. It is up to the library to remove any bytes before calling poll or select again.

Use for example struct.unpack('%uB' % len(data), data) to decode the signal numbers list.

When threads are enabled, this function can only be called from the main thread; attempting to call it from other threads will cause a ValueError exception to be raised.