RTEMS 4.7.2 On-Line Library

Semaphore Manager sem_timedwait - Wait on a Semaphore for a Specified Time

RTEMS POSIX API User's Guide

9.4.8: sem_timedwait - Wait on a Semaphore for a Specified Time

CALLING SEQUENCE:

int sem_timedwait(
  sem_t                 *sem,
  const struct timespec *timeout
);

STATUS CODES:

EAGAIN: The semaphore is not available (i.e., the semaphore value is zero), so the semaphore could not be locked.
EINVAL: The sem argument does not refewr to a valid semaphore

DESCRIPTION:

This function attemtps to lock a semaphore specified by sem, and will wait for the semaphore for an interval specified by timeout. If the semaphore is available, then the semaphore is locked (i.e., the semaphore value is decremented) and the function returns a value of 0. The semaphore remains locked until released by a sem_post() call. If the semaphore is unavailable, then the function will wait for the semaphore to become available for the amount of time specified by timeout.

If the semaphore does not become available within the interval specified by timeout, then the function returns -1 and sets errno to EAGAIN. If any other error occurs, the function returns -1 and sets errno to the appropriate error code.

NOTES:

Multiprocessing is not supported in this implementation.

RTEMS POSIX API User's Guide