signed BaseType_t *pxHigherPriorityTaskWoken
A version of xSemaphoreTake() that can be called from
an ISR. Unlike xSemaphoreTake(), xSemaphoreTakeFromISR() does not permit a block
time to be specified.
|xSemaphore ||The semaphore being 'taken'. A semaphore is referenced by a variable of type SemaphoreHandle_t and must be explicitly created before being used.|
|pxHigherPriorityTaskWoken ||It is possible (although unlikely, and dependent on the semaphore type) that a semaphore will have one or more tasks blocked on it waiting to give the semaphore. Calling xSemaphoreTakeFromISR() will make a task that was blocked waiting to give the semaphore leave the Blocked state. If calling the API function causes a task to leave the Blocked state, and the unblocked task has a priority equal to or higher than the currently executing task (the task that was interrupted), then, internally, the API function will set *pxHigherPriorityTaskWoken to pdTRUE.|
If xSemaphoreTakeFromISR() sets *pxHigherPriorityTaskWoken to pdTRUE, then a context switch should be performed before the interrupt is exited. This will ensure that the interrupt returns directly to the highest priority Ready state task. The mechanism is identical to that used in the xQueueReceiveFromISR() function, and readers are referred to the xQueueReceiveFromISR() documentation for further explanation.
From FreeRTOS V7.3.0 pxHigherPriorityTaskWoken is an optional parameter and can be set to NULL.
- pdTRUE if the semaphore was successfully taken. pdFALSE if the semaphore was not successfully taken because it was not available.
Copyright (C) 2004-2010 Richard Barry. Copyright (C) 2010-2016 Real Time Engineers Ltd.
Any and all data, files, source code, html content and documentation included in the FreeRTOSTM distribution or available on this site are the exclusive property of Real Time Engineers Ltd..
See the files license.txt (included in the distribution) and this copyright notice for more information. FreeRTOSTM and FreeRTOS.orgTM are trade marks of Real Time Engineers Ltd.