RTEMS 4.9.4 On-Line Library

Signal Manager ualarm - Schedule Alarm in Microseconds

RTEMS POSIX API User's Guide

2.4.19: ualarm - Schedule Alarm in Microseconds

CALLING SEQUENCE:

#include <unistd.h>

useconds_t ualarm(
  useconds_t useconds,
  useconds_t interval
);

STATUS CODES:

This call always succeeds.

If there was a previous ualarm() request with time remaining, then this routine returns the number of seconds until that outstanding alarm would have fired. If no previous alarm() request was outstanding, then zero is returned.

DESCRIPTION:

The ualarm() service causes the SIGALRM signal to be generated after the number of microseconds specified by useconds has elapsed.

When interval is non-zero, repeated timeout notification occurs with a period in microseconds specified by interval.

NOTES:

Alarm requests do not queue. If alarm is called while a previous request is outstanding, the call will result in rescheduling the time at which the SIGALRM signal will be generated.

If the notification signal, SIGALRM, is not caught or ignored, the calling process is terminated.

RTEMS POSIX API User's Guide