Find the Length of a Character String in CL, Take Two

December 7, 2005 Hey, Ted

Just yesterday, I was trying to determine the length of the value of a CL variable, so your tip today using the MSGDTA trick was helpful. I was thinking that IBM had added %TRIM and %LEN to the list of CL built-in functions (BIFs) that exist in recent releases, but I guess I was imagining this. Why hasn’t IBM done this, with all the other great enhancements to CL recently? Is there a way to add your own BIFs to CL by creating your own commands?

–Flagler

I have long advocated the creation of commands to extend the CL language, but I find that many programmers have never created a command. So, yes, I think you have a good idea by suggesting the use of commands, even though the commands you create are not true built-in functions.

One reader, Steve, sent in a command he uses to determine the length of character values up to 2000 bytes long. Here’s the command definition source code.

/* Command: RTVVARLEN                     */
/* CPP: RTVVARLENC                        */
/* Retrieve the length of a CL variable   */
/* without trailing blanks                */
 CMD     PROMPT('Return the length of a CL var')
 PARM    KWD(STRING) TYPE(*CHAR) LEN(2000) MIN(1) +
           EXPR(*YES) VARY(*YES) CHOICE('String +
           variable') PROMPT('String variable to check')
 PARM    KWD(LEN) TYPE(*DEC) LEN(4) RTNVAL(*YES) +
           MIN(1) PROMPT('Return variable (4,0)')

Steve didn’t tell me what he calls his command, so I used the name RTVVARLEN (Retrieve Variable Length). Here’s the command to create the command.

CRTCMD CMD(xxx/RTVVARLEN)
       PGM(*LIBL/RTVVARLENC)
       SRCFILE(xxx/QCMDSRC)
       ALLOW(*BPGM *IPGM *BREXX *IREXX)

The command-processing program is short and simple.

/* Retrieve the length of a CL variable */
/* with trailing blanks removed */
PGM        PARM(&STRING &LEN)
DCL        VAR(&STRING) TYPE(*CHAR) LEN(2000)
DCL        VAR(&LEN) TYPE(*DEC) LEN(4 0)
CHGVAR     VAR(&LEN) VALUE(%BIN(&STRING 1 2))

I called the program RTVVARLENC and implemented it as an ILE program compiled to run in the calling program’s activation group.

CRTBNDCL PGM(xxx/RTVVARLENC)
         SRCFILE(xxx/QCLSRC)
         SRCMBR(RTVVARLENC)
         DFTACTGRP(*NO)
         ACTGRP(*CALLER)

Last, here’s the program I used to test Steve’s command. I called it RTVVARLENT.

PGM        PARM(&P1)
DCL        VAR(&P1) TYPE(*CHAR) LEN(32)
DCL        VAR(&LEN) TYPE(*DEC) LEN(4)
RTVVARLEN  STRING(&P1) LEN(&LEN)
DMPCLPGM

I found it returned the correct length of anything I passed to it in the first parameter.

I can’t answer the first question, but I am encouraged by the enhancements IBM made to the CL compiler in V5R3 and am hopeful that we will see more and better things in future releases.

–Ted

RELATED STORY

Find the Length of a Character String in CL