Start a child process in COBOL

Question

How to start a child process in GnuCOBOL?

In Node.js, we can use either spawn or exec to start child processes:

var proc = require("child_process").spawn("ls", ["-l"]);
proc.stdout.on("data", function (chunk) {
  console.log(chunk);
});

// or

var proc = require("child_process").exec("ls -l"], function (err, stdout, stderr) {
   ...
});

Both of the examples above run ls -l (list the files and directories). How can the same thing be achieved in COBOL?

What Cobol ???; in Mainframe CICS/Cobol you would use the CICS START command — Bruce Martin, May 05 '16 at 21:32
@BruceMartin I'm using `GNUCobol`. Could you add an example? — Ionică Bizău, May 06 '16 at 03:35
Not something I can answer. I have copied the question to GNU Cobol forum (https://sourceforge.net/p/open-cobol/discussion/help/thread/8ae787f2/) so they are aware of it; I would imagine Bill/Brian will answer it shortly. Also added GNU-Cobol tag — Bruce Martin, May 06 '16 at 04:58

score 5 · Accepted Answer · answered May 06 '16 at 05:45

Use a common COBOL extension which is supported since years in GnuCOBOL (formerly OpenCOBOL), too:

CALL 'SYSTEM' USING whatever END-CALL

This works with 'cobcrun', too and can be useful if you need a COBOL process with a separate environment (EXTERNAL items, ACCEPT x FROM y / SET ENVIRONMENT y TO x) or runtime configuration (for example via cobcrun -c different.cfg OTHERMAIN).

Your original sample may look like (without the option to use pipes which would be a different question):

CALL 'SYSTEM' USING 'ls -l >dirlist'
  ON EXCEPTION
    CALL 'SYSTEM' USING 'dir >dirlist'
    END-CALL
END-CALL

Afterwards you can read the dirlist as a normal line sequential file.

Simon

BTW: Given your sample you may look for CALL 'C$LISTDIR'.

Brian pointed out http://rosettacode.org/wiki/Fork#COBOL for details on forking in cobol — Bruce Martin, May 07 '16 at 00:16

Start a child process in COBOL

1 Answers1