The pdPropSetAsExtCallback changes the value of an existing PowerDoc property within the PowerDoc object referenced by obj. This function is very similar to and compatible with pdPropSet, which means that the properties changed by this function can be used in much the same capacity as if they were changed by pdPropSet. However, unlike pdPropSet which copies the property value to a buffer that is managed by D-Type Power Engine, this function only adds a special flag which says that the value of this property will be obtained by calling the application's own property callback function, when actually needed. See pdDocSetPropCallback for information on how to set up and use the property callback function. Since the property value itself does not reside inside the associated Power Engine document and is always under exclusive control of the application, the changed property occupies a very small amount of storage space in the object obj (only the amount it takes to store the flag that tells D-Type Engine to obtain its value by calling the callback function).
pdPropSetAsExtCallback is a specialized and advanced function that should be used only by applications that wish to store very large property values (e.g. large arrays or bitmap images) outside the associated Power Engine document, in order to perform their own run-time memory management of large blocks of data. In all other cases pdPropSet should be used instead.
Parameter | Description |
---|---|
power_doc |
Handle of the associated Power Engine document. |
obj |
Object's index in the Power Engine document. |
name |
A numerical value that identifies the property to be changed. Can be a user-defined value or one of the predefined PowerDoc values. For a list of predefined name values, see the pdPropAdd function. |
user_id | |
user_param |
See pdPropSet.
See pdPropSet.
pdPropSet
pdPropAddAsExtCallback