get_message_queue_paramT_get_message_queue_paramGetMessageQueueParamGetMessageQueueParamget_message_queue_param (算子)
名称
get_message_queue_paramT_get_message_queue_paramGetMessageQueueParamGetMessageQueueParamget_message_queue_param — 查询消息队列参数或有关队列的信息。
签名
描述
get_message_queue_paramget_message_queue_paramGetMessageQueueParamGetMessageQueueParamGetMessageQueueParamget_message_queue_param 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_paramGetMessageQueueParamGetMessageQueueParamGetMessageQueueParamget_message_queue_param call, passing multiple parameter names
to parameter GenParamNameGenParamNameGenParamNameGenParamNamegenParamNamegen_param_name. The parameter values are returned
in GenParamValueGenParamValueGenParamValueGenParamValuegenParamValuegen_param_value 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""is_empty"：
-
Returns 1 if the queue is empty, 0 otherwise.
- 'message_num'"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""max_message_num"：
Returns the current value of the 'max_message_num'"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_paramSetMessageQueueParamSetMessageQueueParamSetMessageQueueParamset_message_queue_param。The default value -1 stands for no limit.
执行信息
- 多线程类型：可重入（与非独占算子并行运行）。
- 多线程作用域：全局（可从任何线程调用）。
- 未采用并行化处理。
参数
QueueHandleQueueHandleQueueHandleQueueHandlequeueHandlequeue_handle (输入控制) message_queue → HMessageQueue, HTupleHHandleHTupleHtuple (handle) (IntPtr) (HHandle) (handle)
Message queue handle.
元素数量：
QueueHandle == 1
限制：
QueueHandle != 0
GenParamNameGenParamNameGenParamNameGenParamNamegenParamNamegen_param_name (输入控制) string(-array) → HTupleMaybeSequence[str]HTupleHtuple (string) (string) (HString) (char*)
Names of the queue parameters or info queries.
元素数量：
GenParamName == GenParamValue
默认值：
'max_message_num'
"max_message_num"
"max_message_num"
"max_message_num"
"max_message_num"
"max_message_num"
值列表：
'is_empty'"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""max_message_num", 'message_num'"message_num""message_num""message_num""message_num""message_num"
GenParamValueGenParamValueGenParamValueGenParamValuegenParamValuegen_param_value (输出控制) tuple(-array) → HTupleSequence[Union[int, float, str]]HTupleHtuple (string / integer / real) (string / int / long / double) (HString / Hlong / double) (char* / Hlong / double)
Values of the queue parameters or info queries.
元素数量：
GenParamName == GenParamValue
示例（HDevelop）
create_message_queue (QueueHandle)
set_message_queue_param ( QueueHandle, 'max_message_num', 10)
* ...
get_message_queue_param( QueueHandle, 'message_num', Num)
结果
If all the operator parameters are valid, get_message_queue_paramget_message_queue_paramGetMessageQueueParamGetMessageQueueParamGetMessageQueueParamget_message_queue_param 返回 2 ( H_MSG_TRUE )。否则将抛出异常。
可能的前趋
create_message_queuecreate_message_queueCreateMessageQueueCreateMessageQueueCreateMessageQueuecreate_message_queue,
enqueue_messageenqueue_messageEnqueueMessageEnqueueMessageEnqueueMessageenqueue_message,
dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessagedequeue_message
另见
create_message_queuecreate_message_queueCreateMessageQueueCreateMessageQueueCreateMessageQueuecreate_message_queue,
clear_message_queueclear_message_queueClearMessageQueueClearMessageQueueClearMessageQueueclear_message_queue,
enqueue_messageenqueue_messageEnqueueMessageEnqueueMessageEnqueueMessageenqueue_message,
dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessagedequeue_message,
set_message_queue_paramset_message_queue_paramSetMessageQueueParamSetMessageQueueParamSetMessageQueueParamset_message_queue_param,
create_messagecreate_messageCreateMessageCreateMessageCreateMessagecreate_message,
clear_messageclear_messageClearMessageClearMessageClearMessageclear_message,
set_message_tupleset_message_tupleSetMessageTupleSetMessageTupleSetMessageTupleset_message_tuple,
get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTupleget_message_tuple,
set_message_objset_message_objSetMessageObjSetMessageObjSetMessageObjset_message_obj,
get_message_objget_message_objGetMessageObjGetMessageObjGetMessageObjget_message_obj
模块
基础