Menu Service Procedure Interface › Menu Service Procedures

Menu Service Procedures

A menu service procedure interface is available for Common Application Services (CAS) menus.

Menu service procedures are installation written NCL procedures that are available for performing specialized processing on menus.

Menu service procedures provide a convenient means of extending the functionality of menus.

Menu service procedures are optional. You specify the menu service procedure when you define a menu.

A menu service procedure performs site-specific menu processing at defined points during invocation and processing of a menu:

• On initial entry to the menu
• After a user makes a selection but before acting on it
• After a user acts on a selection
• Prior to exiting the menu
• When a user enters an unrecognized command
• If the menu times out when an INWAIT value is specified

You write your own menu service procedures by using the variables described in the following sections.

The variables can be divided into two groups as follows:

• The first group of variables provide information to the procedure and are not modifiable (read-only). In particular, check the value of &$MHOPT to determine the stage of menu processing for you to implement the required special processing.
• The second group of variables are modifiable and enable the procedure to return information to the system.

You can use your own variables in the menu service procedure. However, do not use variable names that start with #MH. The menu service procedure is called with NOSHRVARS=(#MH). After you specify your own variables, these variables are persistent through the different stages of menu processing. That is, if you specify &A = variable_value, the value of this variable is available on each subsequent call to the procedure.