STGOPT

Default
NOSTGOPT
Recommended
STGOPT
Reasoning
This is a new option introduced in V5 that is now orthogonal to OPT. In V4, the STGOPT behavior to remove unreferenced data items and the corresponding code to initialize their VALUE clauses is implied when going from OPT(STD) to OPT(FULL). Since V5, that behavior is now specified independently. Over a set of benchmark programs, the use of STGOPT results in an average 2.8% reduction in the size of the object file at OPT(2), and a maximum reduction of 11.8%.
Considerations
The same considerations that applied in V4 to specifying OPT(FULL) should be used in deciding to use STGOPT in V6. That is, Start of changeyou cannot use neither OPT(FULL) nor STGOPT if you relies upon any of the following data items:End of changeStart of change
  • Unreferenced LOCAL-STORAGE and non-external WORKING-STORAGE level-77 and level-01 elementary data items
  • Non-external level-01 group items if none of their subordinate items are referenced
  • Unreferenced special registers
End of change
Note: The STGOPT option is ignored for data items that have the VOLATILE clause.

related references
STGOPT (Enterprise COBOL for z/OS® Programming Guide)