List Exit Procedure Interface › List Exit Procedures

List Exit Procedures

This chapter describes the list exit procedure interface that is available for Common Application Services (CAS) lists.

List exit procedures are installation-written NCL procedures that are available for lists to perform specialized processing.

List exit procedures are optional. You specify the list exit procedure when you define a list. The list exit procedure is executed by CAS at three processing points: initialization, entry processing, and termination.

You write your own list exit 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. In particular, you should check the value of &$LHOPT to determine the stage of list 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. Some of these variables are set with values already, but the procedure can change those values.

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