High Availability Monitors Version A.03.02 Release Notes

Writing NOF Applications

Description of the NOF API Entry Points

Chapter 296

does not call the supplied callback routine for this verb.

AP_IN_PROGRESS

The verb has not yet completed. The application can

continue with other processing, including issuing other

NOF verbs, provided that they do not depend on the

completion of the current verb. However, the

application should not attempt to examine or modify

the parameters in the VCB supplied to this verb.

SNAplus2 calls the supplied callback routine to

indicate when the verb processing completes. The

application can then examine the VCB parameters.

Using the Asynchronous Entry Point

When using the asynchronous entry point, note the following:

• If an application speciﬁes a null pointer in the

comp_proc

parameter,

the verb will complete synchronously (as though the application

issued the verb using the synchronous entry point).

• If the call to nof_async is made from within an application callback,

specifying a null pointer in the

comp_proc

parameter is not

permitted. In such cases, SNAplus2 rejects the verb with a primary

return code value of AP_PARAMETER_CHECK and a secondary return

code value of AP_SYNC_NOT_ALLOWED.

• The application must not attempt to use or modify any parameters in

the VCB until the callback routine has been called.

• Multiple verbs do not necessarily complete in the order in which they

were issued. In particular, if an application issues an asynchronous

verb followed by a synchronous verb, the completion of the

synchronous verb does not guarantee that the asynchronous verb has

already completed.

The Callback Routine Speciﬁed on the nof_async

Entry Point

When using the asynchronous NOF API entry point, the application

must supply a pointer to a callback routine. SNAplus2 uses this callback

routine both for completion of a verb and also for returning NOF

indications. (The REGISTER_INDICATION_SINK verb is also issued as