    TaskHandle_t xQueueGetMutexHolderFromISR( QueueHandle_t xSemaphore )
    {
        TaskHandle_t pxReturn;

        configASSERT( xSemaphore );

        /* Mutexes cannot be used in interrupt service routines, so the mutex
         * holder should not change in an ISR, and therefore a critical section is
         * not required here. */
        if( ( ( Queue_t * ) xSemaphore )->uxQueueType == queueQUEUE_IS_MUTEX )
        {
            pxReturn = ( ( Queue_t * ) xSemaphore )->u.xSemaphore.xMutexHolder;
        }
        else
        {
            pxReturn = NULL;
        }

        return pxReturn;
    } /*lint !e818 xSemaphore cannot be a pointer to const because it is a typedef. */
