I have an external COBOL-IT function I want to call from my C program. Getting the error "ERRORC2065: 'productid': undeclared identifier

Question

So I have an external COBOL-IT function I want to call from my C program. At the moment I keep getting the error "ERRORC2065: 'productid': undeclared identifier. Same goes for "aantal". My C is a little rusty since I haven't used it in some time so if anyone could help me out, that would be great. If I drop the "&" it also doesn't work.

#include <stdio.h>
#include "libcob.h"
//#pragma linkage (verkoop, COBOL)

extern void verkoop(char *productid, char aantal*);

int main(int argc, char *argv[])
{
    COB_RTD = cob_get_rtd();
    cob_init(rtd, 0, NULL);
    char productid[6] = "000020";
    char aantal[6] = "000200";
    printf("Hello world");  
    verkoop(&productid, &aantal);
    return 0;
}

This is my verkoop function for those who are interested:

*************************************************************
* VERKOOP  
*************************************************************
       IDENTIFICATION DIVISION.
       PROGRAM-ID. VERKOOP.

       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
       SELECT PRODUCTEN ASSIGN TO "BESTANDEN/PRODUCTEN"
           ACCESS MODE IS RANDOM
           ORGANIZATION IS INDEXED
           RECORD KEY IS PRODUCTID
           FILE STATUS IS WS-FILE-STATUS.

       DATA DIVISION.
       FILE SECTION.
       FD  PRODUCTEN BLOCK CONTAINS 10 RECORDS.
       01  PRODUCT.
           02 PRODUCTID PIC X(6).
           02 LEVERANCIERID PIC X(6).
           02 AANTAL PIC 9(6).
       WORKING-STORAGE SECTION.
       77  FOUT PIC X.
           88 PRODUCT-NIET-GEVONDEN VALUE 1.
       77 WS-PRODUCTID PIC X(6).
       77 WS-AANTAL PIC 9(6).
       77 WS-FILE-STATUS PIC XX.
       LINKAGE SECTION.
       01 LS-PRODUCTID PIC X(6).
       01 LS-AANTAL PIC 9(6).
       PROCEDURE DIVISION USING LS-PRODUCTID, LS-AANTAL.

       MAIN.
           PERFORM INITIALISEER
           PERFORM LEES-PRODUCT-IN
           PERFORM LEES-BESTAND
           PERFORM SLUIT-BESTAND
           STOP RUN.

       INITIALISEER.
           MOVE ZEROS TO PRODUCT
           OPEN I-O PRODUCTEN.
*          DISPLAY WS-FILE-STATUS..

       LEES-PRODUCT-IN.
           MOVE LS-PRODUCTID TO WS-PRODUCTID
           MOVE LS-AANTAL TO WS-AANTAL.
*          DISPLAY "GEEF PRODUCTID OP: "
*          ACCEPT WS-PRODUCTID
*          DISPLAY "GEEF AANTAL OP: "
*          ACCEPT WS-AANTAL.

       LEES-BESTAND.
*      DISPLAY "LEES-BESTAND"
       MOVE WS-PRODUCTID TO PRODUCTID
*      DISPLAY PRODUCTID
       READ PRODUCTEN INVALID KEY SET PRODUCT-NIET-GEVONDEN TO TRUE
       END-READ   
       DISPLAY "END-READ" WS-FILE-STATUS    
       IF PRODUCT-NIET-GEVONDEN PERFORM FOUTJE    
       ELSE 
       MOVE WS-PRODUCTID TO PRODUCTID
       SUBTRACT WS-AANTAL FROM AANTAL   
       PERFORM UPDATE-PRODUCT
       END-IF.


      UPDATE-PRODUCT.
        REWRITE PRODUCT INVALID KEY PERFORM FOUTJE.

        SLUIT-BESTAND.
*       DISPLAY "SLUIT-BESTAND"
           CLOSE PRODUCTEN.

        FOUTJE.
           DISPLAY "ER IS EEN FOUT OPGETREDEN"
*          DISPLAY WS-FILE-STATUS
           STOP RUN.

UPDATE: I fixed the problem by declaring productid and aantal on the first lines of my code.

Answer 1

1) Your constant character array is too small to hold the value of the null terminated initial string.

2) As well, your declaration of the function is incorrect.

extern void verkoop(char *productid, char aantal*);

should be

extern void verkoop(char *productid, char *aantal);

(HINT: Look at '*' for aantal);

3) You call the function with invalid parameters. The function call should have been

verkoop(productid, aantal);

Could you share more info about the compiler that you're using ?

Answer 2

Here's the sample C program from your Getting Started manual:

/* hello.c */
#include <libcob.h>
extern int say(char *hello, char *world);
int main()
{
COB_RTD = cob_get_rtd();
int ret;
int return_status;
char hello[7] = "Hello ";
char world[7] = "World!";
cob_init(rtd, 0, NULL);
ret = say(hello, world);
cob_stop_run (rtd, return_status);
return ret;
}

This shows a simple way to exercise the COBOL-IT API from C.

Note that COBOL does not have "strings". A six byte field in COBOL occupies six bytes, and is not terminated by a "null", or anything else.

Data passed "by reference" to a COBOL program can be amended in the COBOL program. It is up to the programmer to ensure that it is not if it shouldn't be.

Answer 3

You must have other compile errors. Your declarations for productid and aantal are not correct.

char productid[6] = "000020";
char aantal[6]    = "000200";

Compiling that with VC++ shows, error C2117: 'productid' : array bounds overflow

They are short one byte, for the null termination in the string literal. Why not just do:

char *productid = "000020";
char *aantal = "000200";