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

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