SPI Programming Manual (G06.24+, H06.03+, J06.03+)

The SPI Procedures

SPI Programming Manual—427506-006

3-4

SSINIT Procedure

An application must use the SSINIT procedure to initialize a command buffer. The

SSINIT procedure initializes an SPI buffer with an appropriate header and places

values in header fields. The previous contents of the buffer are overwritten.

Do not use SSINIT to initialize an event-message buffer. Instead, use EMSINIT, as

described in the

EMS Manual

General Syntax

buffer output

INT .EXT:ref:*

is the buffer that the procedure initializes as an SPI message buffer.

buffer-length input

INT:value

is the buffer length in bytes. Use the length recommended by the subsystem to

which you are sending the message, if one is defined. For NonStop Kernel

subsystems, the recommended buffer length has a name of the form

subsys-VAL-

BUFLEN.

ssid input

INT .EXT:ref:6

is the subsystem ID of the subsystem to which the message is sent. Its structure is

described in Section 2, SPI Concepts and Protocol

. Requesters use this value to

identify the target subsystem, and the version field of the SSID must specify the

version of the subsystem definitions that the requester is using. Servers check the

SSID to verify that they are the intended recipient of the message.

Use the SSID defined by the subsystem to which you are sending the message.

NonStop Kernel subsystems provide an SSID with a name of the form

subsys-

VAL-SSID.

SSINIT ( buffer ! o

, buffer-length ! i

, ssid ! i

, header-type ! i

, [ command ] ! i

, [ object-type ] ! i

, [ max-resp ] ! i

, [ server-version ] ! i

, [ checksum ] ! i

, [ max-field-version ]) ! i