get_message_tupleT_get_message_tupleGetMessageTupleGetMessageTuple (Operator)

Name

get_message_tupleT_get_message_tupleGetMessageTupleGetMessageTuple — Retrieve a tuple associated with the key from the message.

Signature

get_message_tuple( : : MessageHandle, Key : TupleData)

Description

get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTuple retrieves a tuple associated with the KeyKeyKeyKeykey from the message denoted by the MessageHandleMessageHandleMessageHandleMessageHandlemessageHandle. The tuple has to be previously stored to the message using set_message_tupleset_message_tupleSetMessageTupleSetMessageTupleSetMessageTuple.

The operator returns the data in the parameter TupleDataTupleDataTupleDataTupleDatatupleData. The data including strings is copied by the operation, the message can thus be immediately reused.

If the given KeyKeyKeyKeykey is not present in the message or if the data associated with the key is not a tuple, get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTuple fails. Presence of keys and information about the data associated with the key can be verified using get_message_paramget_message_paramGetMessageParamGetMessageParamGetMessageParam.

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

MessageHandleMessageHandleMessageHandleMessageHandlemessageHandle (input_control) message → (handle)

Message handle.

Number of elements: MessageHandle == 1

Restriction: MessageHandle != 0

KeyKeyKeyKeykey (input_control) string → (string / integer)

Key string or integer.

Number of elements: Key == 1

TupleDataTupleDataTupleDataTupleDatatupleData (output_control) tuple(-array) → (string / integer / real / handle)

Tuple value retrieved from the message.

Example (HDevelop)

* ...
get_message_param (Message,'key_exists',['simple_string','foo','my_image'],\
                   KeysPresence)
get_message_param (Message,'key_data_type',['simple_string','my_image'],\
                   KeysType)
get_message_tuple (Message,'simple_string',TupleString)

Result

If the operation succeeds, get_message_tupleget_message_tupleGetMessageTupleGetMessageTupleGetMessageTuple returns 2 (H_MSG_TRUE). Otherwise an exception is raised. Possible error conditions include invalid parameters (handle or key), the required key not found in the message, or other than tuple data associated with given key.

Possible Predecessors

dequeue_messagedequeue_messageDequeueMessageDequeueMessageDequeueMessage

Alternatives

get_message_objget_message_objGetMessageObjGetMessageObjGetMessageObj

Module

Foundation

Operators