Of course you're going to read this entire chapter to understand everything you need to know about writing a local check routine. But we also have what you're really looking for - samples:

• Metal C samples in z/OS® UNIX file system directory /usr/lpp/bcp/samples:
  • hzscchkr.c - Sample Metal C local check routine demonstrating how to issue check messages.
  • hzscchkp.c - Sample Metal C local check demonstrating how to handle parameters and use persistent data.
  • hzscadd.c - Sample Metal C HZSADDCHECK exit routine.
  • hzssmake.mk - Sample Metal C makefile to build sample health checks.
• Assembler samples in SYS1.SAMPLIB:
  • HZSSADCK - Sample assembler HZSADDCHECK exit routine.
  • HZSSCHKP - Sample assembler local check routine.
  • HZSSCHKR - Sample assembler local check routine.
  • HZSSMSGT - Sample message input.

You'll find all these and more check samples on the IBM® Health Checker for z/OS Web page:

http://www-03.ibm.com/servers/eserver/zseries/zos/hchecker/