Expand Management Programming Manual

SECTION 5
SPI PROGRAMMING CONSIDERATIONS FOR THE EXPAND SUBSYSTEM
The Communications Management Programming Manual discusses gen-
eral programming considerations for writing applications that
use the Subsystem Programmatic Interface (SPI) to communicate
with data-communications subsystems like the EXPAND subsystem.
This section discusses SPI programming considerations that are
specific to the EXPAND subsystem.
BUILDING THE COMMAND BUFFER
The following programming considerations apply when an applica-
tion builds the command buffer for an EXPAND command.
The recommended buffer length in bytes for an EXPAND command is a
predefined value with the symbolic name ZEXP-VAL-BUFLEN.
The EXPAND subsystem does not support multiple commands in a
single request message. However, most of the EXPAND commands
accept up to 30 object names in one command, so one command can
affect up to 30 objects. All the objects named in one command
must be of the same object type.
The EXPAND subsystem does not support continuation of a command
across multiple messages, but it does support the special case
of receiving multiple reply messages using the context token, as
described in the Distributed Systems Management (DSM) Programming
Manual .
The command buffers for all EXPAND commands can contain extensi-
ble structured tokens. An extensible structured token that is
to appear in a command should always be initialized by the SPI
procedure SSNULL to ensure that every field of the token is
initialized to its null value. This action is important because
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