HP-UX SNAplus2 NOF Programmer's Guide

Writing NOF Applications
Description of the NOF API Entry Points
Chapter 296
• For completion of verbs, a pointer to the VCB
supplied by the application. The VCB now includes
the returned parameters set by SNAplus2.
corr The correlator value supplied by the application. This
value enables the application to correlate the returned
information with its other processing.
The callback routine need not use all of these parameters (except as
described in “Using the Callback Routine for Indications”). The callback
routine can perform all the necessary processing on the returned
parameters, or it can simply set a variable to inform the NOF application
that the verb has completed.
Returned Values
The callback function does not return any values.
Using the Callback Routine for Indications
Although the application allocates the VCBs for NOF verbs, SNAplus2
allocates the VCBs for indications. Therefore, the application has access
to the VCB information only from within the callback routine; the VCB
pointer that SNAplus2 supplies to the callback routine is not valid
outside the callback routine. The application must either complete all the
required processing from within the callback routine, or it must make a
copy of any VCB data that it needs to use outside this routine.
In the event that the NOF application needs to make a copy of the data
supplied on the callback routine and the NOF application is using a
signal-based scheduling mode, an operating system limitation may
prohibit memory allocation. In this case, some memory must be
preallocated before the REGISTER_INDICATION_SINK verb is issued.
For more information about signal-based scheduling mode, see
“Signal-Based Scheduling Mode”.
Scope of Target Handle
Each application that needs to use NOF must issue the
CONNECT_NODE verb to obtain its own handle. No two NOF
applications can use the same NOF target handle.