Using the Macros

All macros described in this manual are written in assembler format statements, they are supplied by IBM® in sublibraries. They consist of a number of fields as discussed under Macro Notation. When you code your own macros, you must manage them yourself.

The assembler expands the macro into executable machine instructions and data fields, or both, in the form of assembly language statements. The executable machine instructions typically consist of a branch around the data fields, instructions that load registers, and an instruction that gives control to the system. The macro expansion appears as part of the assembler output listing.

The data fields that are derived from the macro operands, are used at execution time by the control program routine that performs the z/VSE service associated with the macro.

z/VSE offers two different types of macros: data management (IOCS) and system control macros. The data management macros define the characteristics of a file and identify the I/O operation to be performed on the file. The system control macros enable you to make use of control functions available under z/VSE.