GEOS SDK TechDocs
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5 Generic Trees
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7 Special Message Passing
Within
GenClass
, much of your instance data will appear within the basic instance fields allocated with
@instance
. These instance data fields are fixed; each generic object you create will contain each one of these instance fields. You may also make use of special instance data (variable data, also called "vardata") using the object variable data storage mechanism. See the GEOS Programming chapter for complete information on variable data.
Vardata performs many of the same functions that fixed instance data does.
However,
vardata differs significantly from fixed instance data in that it will only occupy memory if it is in fact declared. You may also only access vardata entries through special kernel routines and messages. For generic objects, most vardata is either in the form of attributes (beginning with ATTR_) or hints (beginning with HINT_).
GEOS SDK TechDocs
|
|
| 5 Generic Trees
| 7 Special Message Passing