CICS® Transaction Server for z/OS® offers a number of programming interfaces. The application programming interfsace is widely used by CICS transactions running in a CICS environment. The exit programming interface can be used in a restricted environment that enables the customization of CICS to specific requirements, such as in global user exit programs.
The CICS application programming interface (CICS API) can be used from programs written in any of the high level programming languages supported by CICS, as well as in assembler programs. However, the exit programming interface (XPI) is provided to allow access to some of the CICS services from user exit programs, and these programs must be written in assembler. With the new support in this release, it is now possible for a C language program using the Metal C option to also use the CICS exit programming interface. This opens up the possibility of writing global user exit code using Metal C as a high level language alternative to assembler.
This topic contains some programming examples that demonstrate how the CICS XPI and the CICS API can be used in Metal C.