pub fn read_pid_file(path: &Path) -> Option<u32>Expand description
Read a PID file. A missing file is None. A file whose content is not a
signalable PID (empty, garbage, negative, 0, 1, above i32::MAX) is
reported with a warning, removed as stale, and also None: such a value
must never reach kill(2), where 0 is the own process group and a
wrapped -1 is every process of the user.