Two source-level versions of the default program are provided: DFHPEP, coded in assembler language, and DFHPEPD, coded in C. Both are in the CICSTS31.CICS.SDFHSAMP library. There is an assembler-language macro, DFHPCOM, and a corresponding C copy book, DFHPCOMD, that you can use to define the communication area. These are found in the CICSTS31.CICS.SDFHMAC and CICSTS31.CICS.SDFHC370 libraries, respectively.
You can code your program error program in any of the languages supported by CICS®, but you must always name it DFHPEP.