OMadd_notify_req, OMdel_notify_req

Synopsis

void OMadd_notify_req (OMobj_id object_id,
OMobj_id template_id,OMobj_id method_id,
OMobj_id argument_id, unsigned int event_mask,int mode );
void OMdel_notify_req (OMobj_id object_id,OMobj_id template_id,
OMobj_id method_id,OMobj_id argument_id,
unsigned int event_mask, int mode );

Description

These routines add or delete a notification request. These routines are used by method objects to implement their callback functionality. You do not typically need to call them yourself.

Arguments

object_id

The id of the object on which to place the notification request. That is, a notification request is to be generated when an event occurs in object_id .

template_id

The optional id of a template of subobjects on which to place the notification. See Example 2 below.To indicate no object, specify OMnull_obj.

method_id

The id of the method object to be notified when the event occurs.

argument_id

An optional object id to be passed to the invoked function. To indicate no id, specify OMnull_obj.

event_mask

The events that, when they occur in object_id , will cause a notification on the function.The events are as follows:

Event name

Event

Properties (see notes a and b)

OM_EVENT_VAL

Value changed

Propagated Queued

OM_EVENT_ADD_SUBOBJ

Subobject added

Not propagated Queued

OM_EVENT_DEL_SUBOBJ

Subobject deleted

Not propagated Not queued

OM_EVENT_INST

Object instanced

Not propagated Queued

OM_EVENT_ATT

Attribute changed

Not propagated Queued

OM_EVENT_DEL

Object about to be deleted

Not propagated Not queued

OM_EVENT_PROP

Property changed

Not propagated Queued

Notes:1. a. Propagated means that the notification request extends to objects referenced in the object_id 's value parameter, and to objects referenced by those objects, and so forth.Queued means that if the notification is generated, it is added to AVS/Express' internal queue of notifications to process. Not queued means that AVS/Express processes the notifications immediately.

mode

Options when adding notifications. mode is ignored in a call to OMdel_notify_req.mode can be any of the following. You can OR together individual modes.

Mode

Meaning

0

No options apply.

OM_NOTIFY_NOSUBOBJS

The notification is generated only if an event occurs on object_id itself. By default, a notification is generated if the event occurs on either object_id or any of its subobjects.

OM_NOTIFY_IMM

If the notification is generated, it is processed immediately, even if its property is queued on the events specified.

Example 1

/* Notify myfunc_id when val1_id's property has changed.
___Pass myfunc_id as an argument. */
OMobj_id myfunc_id, val1_id,my_arg;
...
OMadd_notify_req(val1_id, OMnull_obj, myfunc_id, my_arg,
OM_EVENT_PROP, 0);

Example 2

Here is an example of using template_id .The V code below defines group g3 as follows:

group g1 {
int a;
int b;
};
group g2 {
int c;
};
g1+g2 g3 {
int d;
};

If you put a notification request on g3, by default a notification will be generated if any of g3's subobjects change, including subobjects a, b, c, and d.To limit the notification to g3 and the subobjects inherited from g1, you can do the following:

OMobj_id myfunc_id, g3_id, g1_id, my_arg;
...
OMadd_notify_req(g3_id, g1_id, myfunc_id, may_arg,
OM_EVENT_VAL, 0);

See Also

none.