Excellent set of 20 AS400 / RPGLE / CL interview questions 🙌
I’ll answer them one by one, with clarity and examples.

1. How SFLSIZ and SFLPAG differs with all 3 types of Subfiles?

• SFLSIZ = total subfile size (number of records that can be loaded).

• SFLPAG = number of records displayed at a time (one page).

• Types:

  • Load-All: SFLSIZ = large enough for all records; SFLPAG = screen limit (e.g. 10).

  • Expanding: SFLSIZ > SFLPAG; subfile grows as you load records.

  • Rolling: SFLSIZ = SFLPAG; when user pages down, earlier records are removed and new ones added.

2. How to identify whether any job is interactive or batch?

• In CL: RTVJOBA JOBTYPE(&TYPE) → *INTERACT or *BATCH.

• In RPG: Use API QUSRJOBI to retrieve job info.

• Normally: WRKACTJOB → Subsystem *QINTER = interactive, *QBATCH = batch.

3. How will I explicitly open a file in RPG program?

• Specify USROPN in F-spec:

FMYFILE IF E K DISK USROPN
/Free
  OPEN MYFILE;
  CLOSE MYFILE;
/End-Free

4. How do you set pointer to some value or its next or higher value?

• Use SETLL: sets record pointer to equal or next higher key.

• Use SETGT: sets record pointer to strictly greater key.

5. How can we execute a job in AS400?

• Submit to batch: SBMJOB CMD(CALL PGM(MYPGM)) JOB(MYJOB).

• Interactive: call directly: CALL PGM(MYPGM).

6. How can we translate values from lower to upper in RPG and Embedded SQL?

• In RPG: %XLATE('abcdefghijklmnopqrstuvwxyz':'ABCDEFGHIJKLMNOPQRSTUVWXYZ':Var).

• In Embedded SQL: UPPER(column_name).

7. How can we write and read a value using DSPF in CL program?

• Use SNDRCVF RCDFMT(FORMAT1) to display and receive input.

• Then read variables declared in CL with DCL.

8. How to check end of file in CL?

• Use RCVF command inside loop.

• Monitor for message CPF0864 (end of file).

9. Can you update a database file in CL?

• Direct update not possible in CL.

• You must use RUNSQL or call RPG/SQL program to update.

10. How do you monitor the message in CL?

• Use MONMSG after command:

RCVF
MONMSG CPF0864 EXEC(GOTO ENDOF)

11. What is CA and CF and difference between them?

• CA (Command Attention key): Immediate action keys (e.g., F3=Exit).

• CF (Command Function key): Function-related keys that send data back to program.

• Difference: CA = exit/attention, CF = normal function.

12. What can be done from O specs in RPG?

• O-Specs (Output specs) used for report writing.

• Formatting, line spacing, printing variables. (Mostly obsolete in RPG IV; replaced by printer files).

13. What is *PSSR?

• Program Status Subroutine.

• Error-handling routine in RPG called automatically on program error.

• Can retrieve error info from DS like INFDS.

14. Why we use *INLR = *ON?

• To indicate program end, close files, release storage.

• Without it, program remains resident in memory.

15. What we called the program variable used with embedded SQL?

• Host Variables.

• Declared in RPG (DCL-S) and referenced in SQL with :VAR.

16. How to find dependents of a file in AS400?

• Command: DSPDBR FILE(MYLIB/MYFILE) → shows dependent files, programs, etc.

17. What is the length of variable in DCL VAR(&VAR1) TYPE(*CHAR)?

• By default length = 1 unless LEN specified.

• Example: DCL VAR(&VAR1) TYPE(*CHAR) LEN(10) = 10 chars.

18. What is the length of variable in DCL VAR(&VAR2) TYPE(*DEC)?

• Default length = 15,5 (15 total digits, 5 decimals).

• Example: DCL VAR(&VAR2) TYPE(*DEC) LEN(7 2) = 7 digits with 2 decimals.

19. What is the disadvantage of a global variable in AS400?

• Global variables consume memory throughout program execution.

• Risk of unintended value changes across procedures.

• Not thread-safe in multi-activation group environment.

20. How can we avoid using indicators in RPG?

• Use Built-in Functions (BIFs) like %EOF, %FOUND, %ERROR.

• Example:

If %EOF(MyFile);
  // End of file reached
EndIf;

✅ That’s a complete answer set.

AS400 interview questions - Part 1