LOS_QueueRead

Queue

Read a queue.

Description:: This API is used to read the address of data in a specified queue, and store it to the address specified by pBufferAddr.

注意:

The specific queue should be created firstly.
Queue reading adopts the fist in first out (FIFO) mode. The data that is first stored in the queue is read first.
pBufferAddr stores the obtained data address.
Do not read or write a queue in unblocking modes such as an interrupt.
This API cannot be called before the Huawei LiteOS is initialized.
The argument uwTimeOut is a relative time.
The uwBufferSize is not really used in LOS_QueueRead, because the interface is only used to obtain the address of data.
The buffer which the pBufferAddr pointing to must be greater than or equal to 4 bytes.

参数:

	参数名称	描述
	uwQueueID	[IN] Queue ID created by LOS_QueueCreate. The value range is [1,LOSCFG_BASE_IPC_QUEUE_LIMIT].
	pBufferAddr	[OUT] Starting address that stores the obtained data. The starting address must not be null.
	uwBufferSize	[IN] Passed-in buffer size, which must not be 0. The value range is [1,0xffffffff].
	uwTimeOut	[IN] Expiry time. The value range is [0,LOS_WAIT_FOREVER](unit: Tick).

返回值:

	返回值	描述
	LOS_OK	The queue is successfully read.
	LOS_ERRNO_QUEUE_INVALID	The handle of the queue that is being read is invalid.
	LOS_ERRNO_QUEUE_READ_PTR_NULL	The pointer passed in during queue reading is null.
	LOS_ERRNO_QUEUE_READSIZE_ISZERO	The buffer size passed in during queue reading is 0.
	LOS_ERRNO_QUEUE_READ_IN_INTERRUPT	The queue cannot be read during an interrupt when the time for waiting to processing the queue expires.
	LOS_ERRNO_QUEUE_NOT_CREATE	The queue to be read is not created.
	LOS_ERRNO_QUEUE_ISEMPTY	No resource is in the queue that is being read when the time for waiting to processing the queue expires.
	LOS_ERRNO_QUEUE_PEND_IN_LOCK	The task is forbidden to be blocked on a queue when the task is locked.
	LOS_ERRNO_QUEUE_TIMEOUT	The time set for waiting to processing the queue expires.

Dependency: