get_message_paramget_message_paramGetMessageParamGetMessageParam (Operator)

Name

get_message_paramget_message_paramGetMessageParamGetMessageParam — Query message parameters or information about the message.

Signature

Description

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

With each call of get_message_paramget_message_paramGetMessageParamGetMessageParamGetMessageParam, only a single parameter value can be queried. However, there are two types of parameters/queries:

• Parameters/queries applicable to the entire message. In this case no keys must be specified, the parameter KeyKeyKeyKeykey must be an empty tuple.

• Parameters/queries applicable to the individual keys. In this case a non-empty list of keys must be specified in the parameter KeyKeyKeyKeykey. The keys are processed in the same order as specified in the KeyKeyKeyKeykey parameter.

Key-independent (global) parameter names:

'message_keys'"message_keys""message_keys""message_keys""message_keys":

Queries all the keys stored in the message, no matter whether they are associated with tuple or object data. The list of keys is reported as a string tuple via GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue. For this query the parameter KeyKeyKeyKeykey must be an empty tuple.

Currently supported key-specific parameter names are:

'key_exists'"key_exists""key_exists""key_exists""key_exists":

Reports 1 if the given key is stored in the message, 0 otherwise. The results are reported via GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue, one value for each key.

'key_data_type'"key_data_type""key_data_type""key_data_type""key_data_type":

Reports 'tuple'"tuple""tuple""tuple""tuple" for keys associated with tuple data within the message (the data can be retrieved using get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTuple). Reports 'object'"object""object""object""object" for keys associated with object data (the data can be retrieved using get_message_objget_message_objGetMessageObjGetMessageObjGetMessageObj). The results are reported via GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue, one value for each key. This parameter is useful to decide dynamically whether to use get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTuple or get_message_objget_message_objGetMessageObjGetMessageObjGetMessageObj to get the data of a specific key.

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

Example (HDevelop)

get_message_param (Message, 'message_keys', [], AllKeys)
get_message_param (Message, 'key_data_type', AllKeys, KeysType)

Result

If all the operator parameters, and the specified keys are valid, get_message_paramget_message_paramGetMessageParamGetMessageParamGetMessageParam returns 2 (H_MSG_TRUE). Otherwise an exception is raised.

Possible Predecessors

dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessage

See also

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, set_message_paramset_message_paramSetMessageParamSetMessageParamSetMessageParam, enqueue_messageenqueue_messageEnqueueMessageEnqueueMessageEnqueueMessage, dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessage

Module

Foundation