| Operators |
set_message_param — Set message parameter or invoke commands on the message.
set_message_param( : : MessageHandle, GenParamName, Key, GenParamValue : )
set_message_param sets message parameters or invokes action commands on the message.
For each call of set_message_param, only a single parameter can be set. However, there are two types of parameters/commands:
Parameters/commands applicable to the entire message. In this case no keys must be specified, i.e., the parameter Key must be an empty tuple.
Parameters/commands applicable to the individual keys. In this case a non-empty list of keys must be specified in parameter Key. The keys are processed in the same order as specified in the Key parameter.
Key-independent parameter names:
Removes all the keys currently stored in the message and releases all the (control or iconic) data associated with those keys. The operation results in an empty message. Note that contents of GenParamValue is ignored for this parameter, while Key must be an empty tuple.
Key-specific parameter names:
Removes the keys specified in the Key parameter and releases all the (tuple or object) data associated with those keys. If an error occures while processing one or more keys (in particular if the key is invalid), the operator attempts to continue removing as many keys as possible before reporting the failure. Note that the contents of GenParamValue is ignored for this parameter.
This operator modifies the state of the following input parameter:
The value of this parameter may not be shared across multiple threads without external synchronization.Message handle.
Number of elements: MessageHandle == 1
Restriction: MessageHandle != 0
Names of the message parameters or action commands.
Number of elements: GenParamName == 1
Default value: 'remove_key'
List of values: 'remove_all_keys', 'remove_key'
Message keys the parameter/command should be applied to.
Restriction: length(Key) > 0
Values of the message parameters or action commands.
* Remove some keys set_message_param (Message, 'remove_key', ['my_image', 'simple_string'], [])
If all the operator parameters, and their values, as well as specified keys are valid, set_message_param returns 2 (H_MSG_TRUE). Otherwise an exception is raised.
dequeue_message, create_message
enqueue_message, clear_message
create_message, clear_message, set_message_tuple, get_message_tuple, set_message_obj, get_message_obj, get_message_param, enqueue_message, dequeue_message
Foundation
| Operators |