fn on_signal(sig: c_int, h: unsafe extern "C" fn(c_int))Expand description
Install h for sig, without SA_RESTART.
The flag is omitted because it buys nothing here, not because poll_in
needs it: poll(2) is on signal(7)’s list of calls the kernel never
restarts whatever the flag says, and the read(2) in the same loop runs
under VMIN 0 / VTIME 0, so it returns immediately and is never sitting in a
restartable wait either. What makes a resize wake poll_in is installing a
handler at all — SIGWINCH’s default disposition is to discard the signal,
and a discarded signal interrupts nothing.