SNAX/APC Management Programming Manual

Management Programming for SNAX/APC
Introduction to SNAX/APC
1–8 111813 Tandem Computers Incorporated
Security
SNAX/APC commands are classified as either sensitive or nonsensitive. Sensitive
commands can only be issued by users with the super group ID (or any member of the
same user group that started the SNAX/APC process). Nonsensitive commands can
be issued by any user. Section 5, “Commands and Responses,” describes which
commands are sensitive and which are nonsensitive.
Event Messages
When SNAX/APC events occur, SNAX/APC transmits them to the event collector.
The event collector writes the events to the event log. An application can collect
SNAX/APC event messages by creating an EMS consumer-distributor process. The
consumer distributor may specify a user-written filter, which indicates the specific
types of messages that the application needs to collect. After creating the new
consumer-distributor process, the application opens it. The application consumer
distributors scan the event log. When a consumer distributor finds an event message
that matches criteria specified by its filter, it reports the event to the DSM application
that created it.
The application requests event messages by issuing a WRITEREAD (or equivalent)
request. The consumer-distributor process responds when it finds an event message
that matches the criteria specified in the filter.
Like the SPI command buffers, the event-message buffers contain tokens.
Applications can use EMS routines to extract event-message tokens from the event-
message buffer or to format text messages from the event-message buffer.
Creating a consumer distributor, writing a filter, and using the EMS routines are
described in the Event Management Service (EMS) Manual. The event messages issued
by SNAX/APC are described in Section 6, “Operator Messages.”
Empty Response
User-written DSM applications using SPI to communicate with SNAX/APC may
receive an empty response from SNAX/APC. An empty response contains only a
return token indicating that there are no more response records. This should not be
treated as an error condition.
Error Handling
Appendix A describes the errors that SNAX/APC can return in the tokens ZSPI-TKN-
RETCODE and ZSPI-TKN-ERROR. Consult the SPI Common Extensions Manual for a
complete list of data communications error messages and their formats.