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get_message_queue_paramGetMessageQueueParamGetMessageQueueParamget_message_queue_paramT_get_message_queue_param🔗

Short description🔗

get_message_queue_paramGetMessageQueueParamGetMessageQueueParamget_message_queue_paramT_get_message_queue_param — Query message queue parameters or information about the queue.

Signature🔗

get_message_queue_param( message_queue QueueHandle, string GenParamName, out tuple GenParamValue )void GetMessageQueueParam( const HTuple& QueueHandle, const HTuple& GenParamName, HTuple* GenParamValue )static void HOperatorSet.GetMessageQueueParam( HTuple queueHandle, HTuple genParamName, out HTuple genParamValue )def get_message_queue_param( queue_handle: HHandle, gen_param_name: MaybeSequence[str] ) -> Sequence[Union[int, float, str]]

def get_message_queue_param_s( queue_handle: HHandle, gen_param_name: MaybeSequence[str] ) -> Union[int, float, str]Herror T_get_message_queue_param( const Htuple QueueHandle, const Htuple GenParamName, Htuple* GenParamValue )

HTuple HMessageQueue::GetMessageQueueParam( const HTuple& GenParamName ) const

HTuple HMessageQueue::GetMessageQueueParam( const HString& GenParamName ) const

HTuple HMessageQueue::GetMessageQueueParam( const char* GenParamName ) const

HTuple HMessageQueue::GetMessageQueueParam( const wchar_t* GenParamName ) const (Windows only)

HTuple HMessageQueue.GetMessageQueueParam( HTuple genParamName )

HTuple HMessageQueue.GetMessageQueueParam( string genParamName )

Description🔗

get_message_queue_paramGetMessageQueueParam queries current values of message queue parameters or other information about the queue status.

Multiple queries can be carried out with a single get_message_queue_paramGetMessageQueueParam call, passing multiple parameter names to parameter GenParamNamegenParamNamegen_param_name. The parameter values are returned in GenParamValuegenParamValuegen_param_value in the same order as the parameter names requested by the caller.

Currently, following parameter names are supported:

  • 'is_empty'"is_empty": Returns 11 if the queue is empty, 00 otherwise.

  • 'message_num'"message_num": Returns the number of messages currently stored in the queue.

  • 'max_message_num'"max_message_num": Returns the current value of the 'max_message_num'"max_message_num" parameter of the message queue, as it was set using set_message_queue_paramSetMessageQueueParam. The default value -1-1 stands for no limit.

  • 'wait_on_full'"wait_on_full": Returns if enqueue_messageEnqueueMessage would return an error code if the message queue is full, or would wait until space becomes available.

Execution information🔗

Execution information

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).

  • Multithreading scope: global (may be called from any thread).

  • Processed without parallelization.

Parameters🔗

QueueHandlequeueHandlequeue_handle (input_control) message_queue → (handle)HTuple (HHandle)HMessageQueue, HTuple (IntPtr)HHandleHtuple (handle)

Message queue handle.

Number of elements: QueueHandle == 1
Restriction: QueueHandle != 0

GenParamNamegenParamNamegen_param_name (input_control) string(-array) → (string)HTuple (HString)HTuple (string)MaybeSequence[str]Htuple (char*)

Names of the queue parameters or info queries.

Number of elements: GenParamName == GenParamValue
Default: 'max_message_num'"max_message_num"
List of values: 'is_empty', 'max_message_num', 'message_num', 'wait_on_full'"is_empty", "max_message_num", "message_num", "wait_on_full"

GenParamValuegenParamValuegen_param_value (output_control) tuple(-array) → (string / integer / real)HTuple (HString / Hlong / double)HTuple (string / int / long / double)Sequence[Union[int, float, str]]Htuple (char* / Hlong / double)

Values of the queue parameters or info queries.

Number of elements: GenParamName == GenParamValue

Example🔗

(HDevelop)

create_message_queue (QueueHandle)
set_message_queue_param ( QueueHandle, 'max_message_num', 10)
* ...
get_message_queue_param( QueueHandle, 'message_num', Num)

Result🔗

If all the operator parameters are valid, get_message_queue_paramGetMessageQueueParam returns 2 (H_MSG_TRUE). Otherwise an exception is raised.

Combinations with other operators🔗

Combinations

Possible predecessors

create_message_queueCreateMessageQueue, enqueue_messageEnqueueMessage, dequeue_messageDequeueMessage

See also

create_message_queueCreateMessageQueue, clear_message_queueClearMessageQueue, enqueue_messageEnqueueMessage, dequeue_messageDequeueMessage, set_message_queue_paramSetMessageQueueParam, create_messageCreateMessage, clear_messageClearMessage, set_message_tupleSetMessageTuple, get_message_tupleGetMessageTuple, set_message_objSetMessageObj, get_message_objGetMessageObj

Module🔗

Foundation