Same as the sd_pid_* counterparts, but take a pid file descriptor instead of a pid, so that the callers can be sure that the returned values are really about the process they asked for, and not about a recycled PID.
Same as the sd_pid_* counterparts, but take a pid file descriptor instead of a pid, so that the callers can be sure that the returned values are really about the process they asked for, and not about a recycled PID.