How to use a dummy control section

A dummy control section (dummy section) lets you write a sequence of assembler language statements to describe the layout of data located elsewhere in your source module. The assembler produces no object code for statements in a dummy control section, and it reserves no storage in the object module for it. Rather, the dummy section provides a symbolic template or mapping that is empty of data. However, the assembler assigns location values to the symbols you define in a dummy section, relative to its beginning.

Therefore, to use a dummy section, you must:
  • Have access to a storage area for the data
  • Ensure that the locations of the symbols in the dummy section correspond to the locations of the data being described
  • Establish the addressability of the dummy section in combination with the storage area

You can then refer to the data symbolically by using the symbols defined in the dummy section.