Open System Services System Calls Reference Manual (G06.28+)

System Functions (s and S) SPT_FILE_OPEN_(2)
1 Read only
2 Write only
3 Extend (supported only for tape)
The default is 0 (zero).
exclusion Specifies the desired mode of compatibility with other openers of the
file. Valid
values are:
0 Shared
1 Exclusive
2 Process exclusive
3 Protected
The default is 0 (zero).
nowait_depth Specifies whether input/output operations are to be nowait. If present and not 0
(zero), this parameter specifies the number of nowait I/O operations that can be
in progress for the file concurrently with other processing. The maximum value
is 1 for disk files and $RECEIVE. The maximum value is 15 for other objects,
except for the TMF transaction pseudofile (TFILE), which has a maximum of
1000. (Refer to the TMF Application Programmer’s Guide for details about the
TFILE.)
If this parameter is omitted or 0 (zero), I/O operations are waited.
sync_or_receive_depth
The purpose of this parameter depends on the type of device being opened:
disk file Specifies the number of nonretryable (that is, write) requests
whose completion the Guardian file system must remember. A
value of 1 or greater must be specified to recover from a path
failure occurring during a write operation. This value also
implies the number of write operations that the primary process
in a process pair can perform to this file without intervening
checkpoints to its backup process. For disk files, this parameter
is called sync depth. The maximum value is 15.
If omitted, or if 0 (zero) is specified, internal checkpointing does
not occur. Disk path failures are not automatically retried by the
file system.
$RECEIVE file
Specifies the maximum number of incoming messages read by
the SPT_READUPDATEX() function that the application pro-
cess is allowed to queue before corresponding reply operations
must be performed. If omitted or 0 (zero),
SPT_READUPDATEX() and reply operations to $RECEIVE
are not permitted. For $RECEIVE, this parameter is called
receive depth, and the maximum number of queued incoming
messages is 4047.
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