get_message_obj — Retrieve an object associated with the key from the message.
get_message_obj retrives an object associated with the Key from the message denoted by the MessageHandle. The object has to be previously stored to the message using set_message_obj.
The operator returns the data in the parameter ObjectData. The iconic object is copied by the operation. Threrefore, clearing or reusing the message object afterwards will not have any side-effect on the returned iconic object, afterwards.
If the given Key is not present in the message or if the data associated with the key is not an object, get_message_obj fails. Presence of keys and information about the data associated with the key can be verified using get_message_param.
Tuple value retrieved from the message.
Number of elements: MessageHandle == 1
Restriction: MessageHandle != 0
Number of elements: Key == 1
Restriction: length(Key) > 0
* ... 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_obj (Image, Message, 'my_image')
If the operation succeeds, get_message_obj 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 object data associated with given key.
create_message, clear_message, set_message_tuple, get_message_tuple, set_message_obj, set_message_param, get_message_param, enqueue_message, dequeue_message