You can invoke GETMSG from an assembler program or as an assembler service from a program written in a high-level language. The method you use to invoke GETMSG depends on the language your program is written in. For more information about invoking GETMSG as an assembler service from a high-level language, see your language reference.

GETMSG must be invoked in the key and execution state of the calling program. GETMSG must be invoked in 31-bit addressing mode. The caller's parameters must be in the primary address space. It can accept input above or below 16 MB in virtual storage.

Figure 1 shows the standard parameter list structure for GETMSG.

Figure 1. Parameter List Structure for GETMSG Service Parameters