rt_sem_wait2
Semaphore 'wait' operation (with blocking)
Usage
#define MODULE #include <linux/module.h> #include <linux/kernel.h> #include <linux/version.h> #include <linux/errno.h> #include rt_ipc.h
int rt_sem_wait(rt_sem_t *sem, RTIME timeout);
Overview
rt_sem_wait is the semaphore wait (sometimes known as 'take' or 'P') operation. Unlike with rt_sem_trywait, if the semaphore is not available, the calling task blocks until it is. sem points to the structure used in the call to rt_sem_create. An optional timeout can be specified. If timeout is RT_WAIT_FOREVER, the function does not time out. If timeout is RT_NO_WAIT and the semaphore is not available, rt_sem_wait returns immediately. If timeout is any other value, it represent a time at which the call to rt_sem_wait should time out. If that time is reached, rt_sem_wait returns with -ETIME.
Return value
On success, 0 is returned. On failure, a negative value is returned as described below.
Errors
|
The timeout period expired. |
|---|---|
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sem does not point to a valid rt_sem_t. |