When a check runs, it issues messages using the HZSFMSG macro to relate the results of the check. Most of the data for the messages comes from the generated and compiled message table. However, if a message issues dynamic variables (<mv></mv> tags), the variables work as follows:

• The values for the variables must be defined in the HZSMGB data area for the check, which contains an array of pointers to variables.
• The address for the HZSMGB data area for a check is specified on the MGBADDR parameter of the HZSFMSG macro. For example:

  HZSFMSG REQUEST=CHECKMSG,MGBADDR=MGB_PTR

• The message table describes the attributes of the variable, which determine how the variable is formatted. See "Variables for message text" in Message text (<msgtext>) and message variable (<mv>) tags.
• At runtime, when the HZSFMSG macro is issued, the IBM® Health Checker for z/OS® gets the text of the message variable from the address pointed to in the MGB_MsgInsertAddr field in data area HZSMGB.

Figure 1 shows how messages with variables get resolved at check runtime.