Here’s the next 20 Q&A set covering CL, RPGLE, Subfiles, debugging, and modules. I’ll keep them concise but clear 👇

1. What is the maximum length of a variable name in CL program?

• Maximum length = 11 characters.

2. How can we display data from a flat file?

• Use DSPPFM FILE(MYLIB/MYFILE) to display flat file contents.

3. Difference between READC and SFLNXTCHG?

• READC → Reads subfile records that changed (user-modified).

• SFLNXTCHG → Marks records as changed programmatically so they can be read by READC.

4. Difference between ITER and DO?

• ITER → Skips remaining statements in current loop iteration, moves to next iteration.

• DO → Defines start of a loop; works with ENDDO.

5. Difference between RENAME and PREFIX?

• RENAME → Changes record format name while using file in RPG.

• PREFIX → Adds prefix to all field names of a record format (avoids conflicts).

6. How to debug a job which is in MSGW state?

• Use WRKACTJOB → option 5 (Work with job).

• Take option 11 (Work with messages).

• Reply to inquiry message or use STRSRVJOB + STRDBG to debug.

7. How do you pass parameters in CL program?

• Declare parameters using PGM PARM(&VAR1 &VAR2) at top.

• Call program: CALL PGM(MYPGM) PARM('ABC' '123').

8. What is a Spool file?

• A system object storing printed output (reports, job logs, query results).

• Found in *OUTQ (output queues).

9. What does EXFMT do?

• Combines WRITE + READ of a display format.

• Displays screen and waits for user input.

10. What is the default data type of DS subfields in RPGLE?

• Default = Packed Decimal (P) with length 10,0 if no type specified.

11. What is the default data type for decimal 0 in PF?

• Default = Zoned Decimal (Z) with length 5,0.

12. Difference between Packed and Zoned decimal?

• Packed Decimal (COMP-3): 2 digits stored per byte + 1 nibble for sign → storage efficient.

• Zoned Decimal: Each digit stored separately, last nibble stores sign → less storage efficient.

13. Difference between DOW and DOU loop?

• DOW (Do While) → Loop executes while condition is true.

• DOU (Do Until) → Loop executes until condition becomes true (always runs at least once).

14. How do you read a DSPF and Database file in CL program?

• DSPF: Use SNDRCVF command with record format.

• Database file: Use RCVF to read sequentially.

15. How do you declare more than one file in CL program?

• Use multiple DCLF FILE(FILE1) and DCLF FILE(FILE2) statements.

16. How do you declare a file with graphic fields in CL program?

• Use DCLF with a display file that has GRAPHIC data type fields.

17. Why we use %SST in CL program?

• %SST(string start length) extracts a substring from a variable.

• Example: %SST(&VAR 1 3) → returns first 3 characters.

18. Difference between SFLPAG and SFLSIZ?

• SFLPAG = number of records shown per page.

• SFLSIZ = total number of records subfile can hold.

19. Is module executable?

• No. Module (*MODULE) is not executable by itself.

• Must be bound into a program (*PGM) or service program (*SRVPGM).

20. Can we call a module?

• No, modules cannot be directly called.

• You must create a program or service program and call that.

✅ This completes your third set of 20 Q&A.

AS400 interview questions | Answers with explanation 20 questions | Part3