RTOS接口-Semaphores

跟Linux下面的信号量的PV操作是一个思想

接口

/*Create and Initialize a Semaphore object.*/
osSemaphoreId_t  osSemaphoreNew (uint32_t max_count, uint32_t initial_count, const osSemaphoreAttr_t *attr)/*Get name of a Semaphore object.*/
const char *  osSemaphoreGetName (osSemaphoreId_t semaphore_id)/*Acquire a Semaphore token or timeout if no tokens are available.*/
osStatus_t 	osSemaphoreAcquire (osSemaphoreId_t semaphore_id, uint32_t timeout)/*Release a Semaphore token up to the initial maximum count.*/
osStatus_t 	osSemaphoreRelease (osSemaphoreId_t semaphore_id)/*Get current Semaphore token count.*/
uint32_t  osSemaphoreGetCount (osSemaphoreId_t semaphore_id)/*Delete a Semaphore object.*/ 
osStatus_t 	osSemaphoreDelete (osSemaphoreId_t semaphore_id)

代码举例

osSemaphoreId_t multiplex_id;void thread_n (void) {multiplex_id = osSemaphoreNew(3U, 3U, NULL);while(1) {osSemaphoreAcquire(multiplex_id, osWaitForever);// do somethingosSemaphoreRelease(multiplex_id);}
}

当信号量的数量为1时，实现的功能就跟互斥锁没有区别了