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Customizing ViewPoint
ViewPoint Manual—426801-001
6-19
Linkage Section of ZVPT-EXTRAS
ViewPoint application to include custom screens specific to your application or to
display screens of other applications.
The Extras feature allows you to add a custom screen by writing a SCREEN COBOL
program to drive that screen, along with any Pathway servers needed to perform the
functions the operator can request from the new screen. Once you have configured your
custom SCREEN COBOL program and servers, the extras screen and its functions
become part of your ViewPoint application.
Furthermore, you can include additional custom screens, accessible by function keys
from the first custom screen, by adding the necessary SCREEN COBOL programs and
Pathway servers. For instance, you might want your initial Extras screen to be a menu
from which the operator can select any one of several custom screens, each of which
allows the operator to send a different command to a subsystem. The screen for each
command could include fields for entering the command parameters.
Linkage Section of ZVPT-EXTRAS
On standard ViewPoint screens, where the Extras function key is provided, if you press
this key, the result is a call to a SCREEN COBOL program unit named ZVPT-EXTRAS.
If the ZVPT-EXTRAS program unit exists, it takes control of the terminal. If the
program unit does not exist, ViewPoint displays an error message. If you do not want the
EXTRAS program to be executed, you must delete it from the program object library.
Your ZVPT-EXTRAS program unit must have the following PROCEDURE DIVISION
definition:
PROCEDURE DIVISION
USING ZVPT-IPC-HDR,
ZVPT-LINK-DATA-L,
ZVPT-USER-REQUEST.
When the ViewPoint application calls the ZVPT-EXTRAS program, it passes it a
SCREEN COBOL Linkage Section containing context information. This Linkage
Section is shown in Figure 6-4.
Note. The ViewPoint program object files provided by Compaq do not include a
ZVPT-EXTRAS program unit. You should build a separate object library to contain your
ZVPT-EXTRAS program unit.