The MPE/iX System Message Facility consists of two message catalogs:
CATALOG.PUB.SYS, which contains Compatibility Mode system error messages.
SYSCAT.PUB.SYS, which contains Native Mode system error messages.
CATALOG.PUB.SYS is formatted with the MAKECAT utility. Its messages are accessed with the GENMESSAGE intrinsic. CATALOG.PUB.SYS contains messages from procedures executing in Compatibility Mode.
SYSCAT.PUB.SYS is formatted with the GENCAT utility. Its messages are accessed with the CATREAD intrinsic. SYSCAT.PUB.SYS contains messages from procedures executing in Native Mode.
You can only access messages in the System Message Facility; you can't modify the files. For example, you can output error messages from your program without creating your own error message catalog.
Accessing system error messages is discussed in Chapter 5.
