OS_SEM_CTR OSTaskSemPost (OS_TCB *p_tcb, OS_OPT opt, OS_ERR *p_err)File | Called from | Code enabled by |
|---|---|---|
| Task or ISR | Always enabled |
...
Description
OSTaskSemPost() sends a signal to a task through it’s local semaphore.
If the task receiving the signal is actually waiting for a signal to be received, it will be made ready-to-run and, if the receiving task has a higher priority than the task sending the signal, the higher-priority task resumes, and the task sending the signal is suspended; that is, a context switch occurs. Note that scheduling only occurs if if opt is is set to to OS_OPT_POST_NONE, because the the OS_OPT_POST_NO_SCHED option option does not cause the scheduler to be called.
Files
os.h/os_task.c
Prototype
| Code Block |
|---|
OS_SEM_CTR OSTaskSemPost (OS_TCB *p_tcb,
OS_OPT opt,
OS_ERR *p_err) |
Arguments
p_tcb
is a pointer to the TCB of the task being signaled. A NULL pointer indicates that the user is sending a signal to itself.
...
If the call was successful and the signal was sent.
OS_ERR_OPT_INVALID
If OS_CFG_ARG_CHK_EN is set to DEF_ENABLED in os_cfg.h: if a valid option is not specified.
OS_ERR_OS_NOT_RUNNING
If OS_CFG_INVALID_OS_CALLS_CHK_EN is set to DEF_ENABLED in os_cfg.h: if µC/OS-III is not running yet.
OS_ERR_SEM_OVF
the post would have caused the semaphore counter to overflow.
OS_ERR_STATE_INVALID
If the task is in an invalid state.
Returned Value
The current value of the task’s signal counter, or 0 if called from an ISR and OS_CFG_ISR_POST_DEFERRED_EN is set to 1to DEF_ENABLED.
Required Configuration
Always enabled.
Callers
Application and ISRs.
Notes/Warnings
None.
Example Usage
| Code Block | ||
|---|---|---|
| ||
OS_TCB CommRxTaskTCB;
void CommTaskRx (void *p_arg)
{
OS_ERR err;
OS_SEM_CTR ctr;
(void)&p_arg;
while (DEF_ON) {
:
ctr = OSTaskSemPost(&CommRxTaskTCB,
OS_OPT_POST_NONE,
&err);
/* Check "err" */
:
:
}
} |