Metal C or assembler?

As mentioned above, you can write a local or remote check in either Metal C or assembler. The concepts in this section apply to either language.

Metal C lets you create a IBM® Health Checker for z/OS® compatible load module that follows MVS™ linkage conventions. You can also easily use assembler macros, such as HZSFMSG, HZSCPARS, or any other assembler macro, in your Metal C check routine using the __asm keyword.

If you are writing in Metal C, IBM Health Checker for z/OS provides generic C header files (hzsh*.h) in SYS1.SIEAHDRV.H containing the following mappings of IBM Health Checker for z/OS structures and control blocks and commonly used Health Checker related constants:

Table 1. Correlation between IBM Health Checker for z/OS mapping macros and Metal C header files
Assembler mapping macros in SYS1.MACLIB	Description	Metal C header file in SYS1.SIEAHDRV.H
HZSPQE	Individual check data area	HZSHPQE
HZSDPQE	Individual deleted check data area	HZSHDPQE
HZSMGB	Message data area	HZSHMGB
HZSQUAA	HZSQUERY return information data area	HZSHQUAA
HZSZCPAR	Check parameter area	HZSHCPAR
HZSZENF	Event data for ENF 67	HZSHENF
HZSZHCKL	Message buffer log entry	HZSHHCKL
HZSZCONS	Check return and reason codes	HZSHCONS
	Common shared types	HZSHTYPE
	Include that pulls in all the other header files above	HZSH

For detailed information about Metal C, see z/OS Metal C Programming Guide and Reference. You will also want to use the sample checks in Sample local checks.