SeeView Manual

SeeView Statements and Script Symbols
HP NonStop SeeView Manual—526355-004
9-18
ALTER
QUEUE ON | OFF
specifies the value for the QUEUE attribute option for user tasks declared with the
OPEN or TASK statements.
QUEUE OFF, the default, indicates that the SeeView program automatically replies
to all simple write messages from the task.
QUEUE ON indicates that the SeeView program does not automatically reply to
any messages, including simple writes, from the specified task.
Typically, the only time you need to specify QUEUE ON is to assert programmatic
synchronization in a script that preforms complex interleaving of WRITE and READ
statements between multiple processes. Communication synchronization in a script
for a single process is ensured unless WRITE and READ statements are
interleaved with one or more WAIT statements.
RECVTRACE ON | OFF
indicates whether all $RECEIVE reads and replies should be traced to the file
specified with ALTER TRACEFILE filename.
ALTER RECVTRACE ON causes this message traffic to be traced to the trace file.
RECVTRACE OFF is the default. Use this option for debugging purposes only.
REFRESH seconds
specifies the interval in seconds for windows to be automatically updated
(refreshed) with messages received in the user-task message cache.
The default interval is two seconds. Every two seconds, visible windows on the
current page are updated with any messages received.
The standard SeeShell alters the REFRESH value to one second. If another shell
is used and the REFRESH value is not specified, it defaults to two seconds.
Special considerations in connection with this option:
•
The REFRESH algorithm adapts to both terminal user function key operations
and external user-task events. Making the algorithm adaptive minimizes read
cancellation and making the terminal appear fairly full duplex. The algorithm
also eliminates redundant checking of the user cache when it is not changing
and saves CPU cycles.
•
Top-down user-controlled paging of window text is the default for all windows.
Normally, window text is not automatically paged or scrolled ahead. This can
be specified with the WINDOW CACHE EOFSEEK or EOFONLY options.
•
The REFRESH operation occurs in a single input-output operation. Boxcarring
of user-task messages is thus achieved, which minimizes I/O operations.
Boxcarring refers to the technique of blocking an entire group of logical
operations into a single block or boxcar and sending that entire block of