CODEWITHSUNDEEP
cobol
Pavel Matras
Pavel Matras

Reputation: 349

COBOL CALL "SYSTEM" return value

I am using Micro Focus COBOL on Windows system and have this code

.
.
01 w-param pic x(100) value 'dir > out.txt'.
.
.
call "SYSTEM" using w-param

Then I have to read out.txt file to get output from dir command. Is there any way to get output from dir (or any other system command) directly to my program as returning value?

Upvotes: 1

Views: 4876

Answers (2)

Simon Sobisch
Simon Sobisch

Reputation: 7297

Answer - Part 1: NO, you can not have any output of the CALL in the return value.

Answer - Part 2: But you can get the output with a different option.

Explanation for part 1: "return-values" are normally an integer, passed via the special register RETURN-CODE and/or with the RETURNING clause (in some implementations allowing you to additional get a pointer): CALL someprog RETURNING something, see the COBOL documentation for CALL.

Explanation for part 2: What you may can do is to create a pipe and read from there, either with calling the C interface or with an implementor-specific extension.

With ACUCOBOL or MicroFocus [and maybe others] you can use pipes via line sequential file access - see the answer of Stephen Gennard for details on MicroFocus and this answer's end for ACUCOBOL.

On unix you can "natively" create a named pipe with CALL 'SYSTEM', a possible way of reading from there is documented in the GnuCOBOL FAQ -> named pipes, in general you can create a pipe and read from it via C interface.

A sample implementation for using pipes via C interface and a COBOL wrapper for it is cobweb-pipes (MF likely supports user defined functions, therefore the cobweb-pipes.cob likely works more or less unchanged (if you test this please answer with a comment), otherwise the cobweb-call-pipes.cob is very likely to work.

Edit:

Extension in ACUCOBOL via SEQUENTIAL files and starting with a -P in the assigned filename:

      program-id. dircmdread.
      select i-cmd
     * windows:
         assign to "-P %TMP% cmd.exe /c dir > %TMP%"
     * unix:    
     *   assign to "-P ls -l"
         organization is sequential.
      fd i-cmd.
      01 i-cmd-record pic x(80).
      procedure division.
          open input i-cmd
          perform until exit
           read i-cmd
            at end
               exit perform
           end-read
           display i-cmd-record
          end-perform
          close i-cmd
          goback.

Upvotes: 3

Stephen Gennard
Stephen Gennard

Reputation: 1910

Answer: YES (if you are using Micro Focus COBOL)

You can do it by using pipes via COBOL syntax

For example:

   program-id. dircmdread.
   select i-cmd
      assign to "< cmd.exe /c dir"
      organization is line sequential.
   fd i-cmd.
   01 i-cmd-record pic x(80).
   procedure division.
       open input i-cmd
       perform until exit
        read i-cmd
         at end
            exit perform
        end-read
        display i-cmd-record
       end-perform
       close i-cmd
       goback.

   end program dircmdread.

and execute it via:

Y:\DemoAndTests\dirread>cobol dircmdread.cbl nologo int();
* Generating dircmdread
* Data:        1048     Code:         736     Literals:         424

Y:\DemoAndTests\dirread>run dircmdread
 Volume in drive Y is UserSourceCode
 Volume Serial Number is EE5F-1112

 Directory of Y:\DemoAndTests\dirread

29/09/2016  15:13    <DIR>          .
29/09/2016  15:13    <DIR>          ..
29/09/2016  15:16               509 dircmdread.cbl
29/09/2016  15:17             2,560 dircmdread.int
29/09/2016  15:17             2,330 dircmdread.obj
               3 File(s)          5,399 bytes
               2 Dir(s)  20,383,764,480 bytes free

Upvotes: 2

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