You can perform the same tasks with E15 and E35 user exit routines written in COBOL that you can perform with E15 and E35 user exit routines written in assembler. However, COBOL routines differ from assembler routines in the way they pass information between themselves and DFSORT.

• COBOL routines must pass information through fields described in the LINKAGE SECTION of the DATA DIVISION. Assembler uses general register 1 and pointers in a parameter list.
• COBOL routines must use RETURN-CODE, a COBOL special register. Assembler uses register 15 for the return code.
• COBOL routines must use return code 20 to alter or replace a record. Assembler uses return code 0.
• COBOL routines can use the user exit area for E15/E35 communication. Assembler uses the user address constant.