👁 0
Q: How to use PERFORM EXIT?
Answer:
EXIT statement marks paragraph end. PERFORM PROCESS-DATA THRU PROCESS-EXIT. Process-exit paragraph contains only EXIT. Ensures consistent exit point. Can also GO TO exit paragraph. EXIT PROGRAM in subprogram returns to caller.
👁 0
Q: Explain CALL statement and parameters
Answer:
CALL invokes subprogram: CALL 'SUBPROG' USING param-1 param-2. BY REFERENCE (default) passes address. BY CONTENT passes copy. BY VALUE passes value (for C). ON EXCEPTION handles load failures. CANCEL releases memory.
👁 0
Q: What is LINKAGE SECTION?
Answer:
LINKAGE SECTION defines parameters received from calling program. Items here have no memory until CALL provides addresses via USING clause. Address established at runtime. Used for both passed parameters and dynamically addressed data.
👁 0
Q: What is GOBACK vs STOP RUN?
Answer:
STOP RUN terminates entire run unit (all programs). GOBACK returns to caller; if main program, acts like STOP RUN. Use GOBACK in subprograms to return control. STOP RUN from subprogram ends everything unexpectedly.
👁 0
Q: Explain ENTRY statement
Answer:
ENTRY creates alternate entry point in subprogram. ENTRY 'ALTNAME' USING params. Called program appears under different name. Useful for multiple functions in one load module. Each ENTRY has own parameters. Not standard-use carefully.