GEOS SDK TechDocs
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4.1 Creating Types and Lists
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4.3 Handling Application Notification
MSG_META_GCN_LIST_ADD
Registering for application notification is simple once you have created your own custom notification lists. Whenever an object or process needs to be notified of an application change, you should call
MSG_META_GCN_LIST_ADD
to add that object or process to the list interested in that particular change.
MSG_META_GCN_LIST_ADD
finds the appropriate custom GCN list and adds the optr of the new object to the end of that list. (If no space for the list currently exists because it is empty, the message will allocate space for the list automatically.) You may add the interested optr at any time during the process' or object's life, but it is usually convenient for a process to be added in its
MSG_GEN_PROCESS_OPEN_APPLICATION
or for an object to be added in its
MSG_META_ATTACH
handler.
Each optr in a GCN list should have a notification ID attached to it. The combination of a manufacturer ID and a notification type comprises an element's specific notification ID.
MSG_META_GCN_LIST_ADD
must pass the optr of the object to add, along with a notification ID. For each separate notification ID, a separate GCN list is needed and will be created automatically.
Geoworks has several pre-defined GCN lists of type
GeoWorksGenAppGCNListType
for use by applications. You will probably have only limited use for these; these list types are used mostly by the UI controllers. For information on these types and how the various classes use them, see the Controllers chapter.
Code Display 9-4 Adding Yourself to a Custom GCN List
@method MyProcessClass, MSG_GEN_PROCESS_OPEN_APPLICATION {
@callsuper; /* Do default MSG_GEN_PROCESS_OPEN_APPLICATION */
myThread = ConstructOptr(GeodeGetProcessHandle(), NullChunk);
/* myThread (the process) is added to notification of TYPE_ONE changes */
@call MyApplication::MSG_META_GCN_LIST_ADD(myThread,
yourCompanyName_GAGCNLT_CUSTOM_LIST_TYPE_ONE,
MANUFACTURER_ID_yourCompanyName);
}
GEOS SDK TechDocs
|
| 4.1 Creating Types and Lists
| 4.3 Handling Application Notification