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Queue set and semaphore behavior question

Posted by rrrum on May 19, 2016


Suppose I have created queue set "xQueueSetTest" with one queue and semaphore. Then in a task I call

xActivatedMember = xQueueSelectFromSet( xQueueSetTest, portMAX_DELAY );

which will block the task. If semaphore is signaled from some other task, the task unblocks but in subsequent code I don't call

xSemaphoreTake( xActivatedMember, 0 );

If the task is executed again and arrives at xQueueSelectFromSet will it exit immediately since semaphore is still signaled?

Is my understanding correct or the behavior will be again blocked task?



Queue set and semaphore behavior question

Posted by rtel on May 19, 2016

No - the task will block again and that will be a logic error. If a task is blocked on a queue set and leaves the blocked state because an item was posted to a queue or semaphore in that set then the unblocked task MUST them remove the item from the queue or semaphore.

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