This tunable is set by the ACU compiler directive, and once set, cannot be un-set without recompiling your program without the ACU directive.
>>-------acu_library=--.-TRUE-.---------><
+-FALSE+
Aculibs provides certain functionality for ACUCOBOL-GT compatibility. It provides C$RERR, the library routine for obtaining extended error information from file operations, and a number of external variables (F-ERRNO, F-INT-ERRNO, F-INT2-ERRNO, F-ERRMSG, RETURN-CODE, and A4GL-WHERE-CONSTRAINT) containing other error information.
External variables can provide additional information in troubleshooting situations. For example, if a database returns an error that does not map to one of the standard COBOL errors (record locked, duplicate key, etc.), the external variables F-ERRNO, F-INT-ERRNO, F-INT2-ERRNO and F-ERRMSG will contain extra information. Typically, F-ERRNO will be E_INTERNAL (which has a value of 15). F-INT-ERRNO and F-INT2-ERRNO will be the error values returned by the database, and F-ERRMSG will point to a text message returned by the database.
When acu_library is set, ensure you add the following external declarations to working-storage:
01 A4GL-WHERE-CONSTRAINT PIC X(300). 01 F-INT-ERRNO SIGNED-LONG. 01 F-INT2-ERRNO SIGNED-LONG. 01 F-LOG-ERRNO SIGNED-SHORT. 01 F-ERRMSG POINTER. 77 F-ERRNO SIGNED-SHORT. 01 RETURN-CODE SIGNED-LONG.