get_message_queue_paramget_message_queue_paramGetMessageQueueParamGetMessageQueueParam (Operator)

Name

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

Signature

get_message_queue_param( : : QueueHandle, GenParamName : GenParamValue)

get_message_queue_paramget_message_queue_paramGetMessageQueueParamGetMessageQueueParamGetMessageQueueParam 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_paramget_message_queue_paramGetMessageQueueParamGetMessageQueueParamGetMessageQueueParam call, passing multiple parameter names to parameter GenParamNameGenParamNameGenParamNameGenParamNamegenParamName. The parameter values are returned in GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue in the same order as the parameter names requested by the caller.

Currently, following parameter names are supported:

'is_empty'"is_empty""is_empty""is_empty""is_empty":

Returns 1 if the queue is empty, 0 otherwise.

'message_num'"message_num""message_num""message_num""message_num":

Returns the number of messages currently stored in the queue.

'max_message_num'"max_message_num""max_message_num""max_message_num""max_message_num":

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

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

QueueHandleQueueHandleQueueHandleQueueHandlequeueHandle (input_control) message_queue → (integer)

Message queue handle.

Number of elements: QueueHandle == 1

Restriction: QueueHandle != 0

GenParamNameGenParamNameGenParamNameGenParamNamegenParamName (input_control) string(-array) → (string)

Names of the queue parameters or info queries.

Number of elements: GenParamName == GenParamValue

Default value: 'max_message_num' "max_message_num" "max_message_num" "max_message_num" "max_message_num"

List of values: 'is_empty'"is_empty""is_empty""is_empty""is_empty", 'max_message_num'"max_message_num""max_message_num""max_message_num""max_message_num", 'message_num'"message_num""message_num""message_num""message_num"

GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue (output_control) tuple(-array) → (string / integer / real)

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_paramget_message_queue_paramGetMessageQueueParamGetMessageQueueParamGetMessageQueueParam returns 2 (H_MSG_TRUE). Otherwise an exception is raised.

Possible Predecessors

create_message_queuecreate_message_queueCreateMessageQueueCreateMessageQueueCreateMessageQueue, enqueue_messageenqueue_messageEnqueueMessageEnqueueMessageEnqueueMessage, dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessage

create_message_queuecreate_message_queueCreateMessageQueueCreateMessageQueueCreateMessageQueue, clear_message_queueclear_message_queueClearMessageQueueClearMessageQueueClearMessageQueue, enqueue_messageenqueue_messageEnqueueMessageEnqueueMessageEnqueueMessage, dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessage, set_message_queue_paramset_message_queue_paramSetMessageQueueParamSetMessageQueueParamSetMessageQueueParam, create_messagecreate_messageCreateMessageCreateMessageCreateMessage, clear_messageclear_messageClearMessageClearMessageClearMessage, set_message_tupleset_message_tupleSetMessageTupleSetMessageTupleSetMessageTuple, get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTuple, set_message_objset_message_objSetMessageObjSetMessageObjSetMessageObj, get_message_objget_message_objGetMessageObjGetMessageObjGetMessageObj

Module

Foundation

Operators