Exit programs are called and given control by an application program or system program. They can be used to customize particular functions to your needs. An exit program is a program to which control is passed from a calling program.
Exit programs are usually user-written programs; however, a few are system-supplied (such as a few of the Operational Assistant exit programs).
To transfer control to an exit program, you do an external call as you would to any other program.
There are no general requirements for using exit programs. For any specific requirements, see the documentation for the specific exit program.
An exit point signifies the point in a system function or program where control is turned over to one or more exit programs to perform a function.
Prior to Version 3 Release 1, the exit program might have been represented as network attributes, system values, CL command parameters, or attributes of system objects. Also, in previous releases, all exit point providers had to supply their own means of registering and deregistering exit programs.
The registration facility provides a central point to store and retrieve information about i5/OS™ and non-i5/OS exit points and their associated exit programs. This information is stored in the registration facility repository and can be retrieved to determine which exit points and exit programs already exist.
You can use the registration facility APIs to register and deregister exit points, to add and remove exit programs, and to retrieve information about exit points and exit programs. You can also perform some of these functions by using the Work with Registration Information (WRKREGINF) command.
The exit point provider is responsible for defining the exit point information, defining the format in which the exit program receives data, and calling the exit program.