HP-UX SNAplus2 NOF Programmer's Guide

Introduction to the NOF API
NOF Indications
Chapter 1 83
NOF Indications
A NOF application can use the REGISTER_INDICATION_SINK verb to
request information about changes to the SNAplus2 configuration or to
the status of its resources. SNAplus2 then sends an indication message
to the application each time a change occurs.
For a complete list of indications that an application can request, see
Chapter 6, “NOF Indications.”
Except for CONFIG_INDICATION, NOF_STATUS_INDICATION, and
SNA_NET_INDICATION, each indication is returned when a resource of
the specified type changes its status. For example, if the application
registers for DLC indications, SNAplus2 sends a DLC_INDICATION
message to the application each time a DLC becomes active or inactive.
An indication returns summary information about the change that has
occurred. If necessary, the application can then issue the appropriate
QUERY_* verb to obtain more detailed information.
If the local node is short of resources, it can temporarily suppress
indications and not send them to applications. When the resource
shortage condition clears, and the local node subsequently generates an
indication of a type that it has previously suppressed, it then sets a
parameter on the indication to inform the application that one or more
previous indications of this type have been lost. The application should
then issue QUERY_* verbs for the appropriate resource type to
determine the current state of resources.
For more information about registering to receive indications, see . For
more information about individual indications, see Chapter, “Overview.”
Configuration Indications
An application can register to receive information about changes to the
configuration of a particular target (the domain configuration file, a
running node, or an inactive node). This enables it to keep track of
changes that can be made by other NOF applications or by the
administration programs. To do this, the application registers as for
other indications, specifying CONFIG_INDICATION as the requested
indication type.