By default, the runtime searches for functions named "cics_xfh", "cobol_extfh", and "EXTFH" in that order. If your EXTFH function uses a different name, you may also need to set a configuration variable to specify the function name (such as A_EXTFH_FUNC). If necessary, you can also specify a different function name for relative, sequential, and/or indexed files. For more information on A_EXTFH_FUNC and related configuration variables, see A_EXTFH_FUNC.