memcopy not found libcob - c code for cobol compiling linking error

[J McNamara]

Hi all-

I want to use pointers in cobol.

I tried thus so far...

gcc -c -static -o testabc.o testabc.c -lstdc++ -lmsvcrt -nostartfiles
cobc -x -v -fixed dialog.cbsql cobjapi.o japilib.o testabc.o imageio.o fileselect.o -I. -L"c:\msys64\mingw64\bin" -L"c:\msys64\mingw64\bin" -L"c:\msys64\opt\gixsql\lib" -L"c:\msys64\mingw64\bin" -L. -lws2_32 \
 -ljapi \
 -lgixsql \
 -lstdc++ \
 -lmsvcrt \
  -lmingw32

I have the following code AI is helping me with, but it seems that libc is for cygwin more so than mingw. It keeps saying "licob not finding module memcpy". I tried fooling with pointers, and I was so spacy that i thought about using the perl code example brian left, after he even said, 'for display only' ... lol. I rallied and said, I need to get out C book but am having a little trouble with this compile and link scenario.

Here is the offending code...
Please assist - jim

*> Call the C function
           CALL "create_integer_string" USING BY REFERENCE num-array
                                         BY VALUE array-size
                                         RETURNING c-result-pointer.

      *> Check if the returned pointer is not NULL
           IF c-result-pointer NOT = NULL
      *> Call memcpy to copy the C string into the COBOL string
               CALL "memcpy" USING BY REFERENCE c-result-string
                                 BY REFERENCE c-result-pointer
                                 BY VALUE 256
      *> Null-terminate the COBOL string just in case
               MOVE X"00" TO c-result-string(256:1)

               DISPLAY "Result from C: " c-result-string

      *> Free the memory allocated by C
               CALL "free" USING BY REFERENCE c-result-pointer
           ELSE
               DISPLAY "C function returned NULL."
           END-IF.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Function to create and return a string of integers
char *create_integer_string(int *numbers, int size) {
    int estimated_size = size * 16; // Each integer can take up to 16 characters (including space)
    char *buffer = (char *)malloc(estimated_size * sizeof(char));

    if (buffer == NULL) {
        printf("Memory allocation failed\n");
        return NULL;
    }

    char *current = buffer;

    for (int i = 0; i < size; i++) {
        char temp[16];
        sprintf(temp, "%d", numbers[i]);

        if (i > 0) {
            *current = ' ';
            current++;
        }

        // Ensure that memcpy is correctly copying the string and its null terminator
       memcpy(current, temp, strlen(temp) + 1);// Copy string including null terminator
        current += strlen(temp);
    }

    return buffer;  // Returns the dynamically allocated string
}
/*
int main() {
    int numbers[] = {1, 23, 456, 7890};
    int size = sizeof(numbers) / sizeof(numbers[0]);

    char *result = create_integer_string(numbers, size);

    if (result != NULL) {
        printf("Created string: %s\n", result);
        free(result);  // Free the memory when done
    }

    return 0;
}
*/

[J McNamara]

i was reviewing and found out that numbers needed fixing to pointer or array. I guess the ai fell asleep a little.

sorry,
thanks

[J McNamara]

Hi all-

I tried this but I am running out of tries.

This whole winmain thing is killing me with mingw.

I'm certainly a beginner and this one has me STUCK!

thanks

 g++ -mwindows cobjapi.o japilib.o testabc.o imageio.o fileselect.o -L"c:\msys64\opt\gixsql\lib" -L"c:\msys64\mingw64\bin" -L. -L/mingw64/lib -lcob -lws2_32 -ljapi -lgixsql
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/14.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:/msys64/mingw64/lib/libmingw32.a(lib64_libmingw32_a-crtexewin.o): in function `main':
C:/M/B/src/mingw-w64/mingw-w64-crt/crt/crtexewin.c:67:(.text.startup+0xc5): undefined reference to `WinMain'
collect2.exe: error: ld returned 1 exit status

#include <stdio.h>
#include <iostream>
#include <sstream>
#include <string>
#include <cstring>

// Function to create and return a dynamically allocated string of integers
char* create_integer_string(int* numbers, int size) {
    std::ostringstream oss;

    // Append integers to the string stream
    for (int i = 0; i < size; ++i) {
        if (i > 0) oss << " "; // Add space between numbers
        oss << numbers[i];
    }

    // Convert the string stream to a std::string
    std::string result = oss.str();

    // Dynamically allocate memory for the string and copy it
    char* cstr = new char[result.size() + 1];
    std::strcpy(cstr, result.c_str()); // Copy the string content
    return cstr; // Return the pointer to the allocated string
}

// Function to free the memory allocated for the string
void free_string(char* str) {
    delete[] str;
}

int wmain(int argc, wchar_t** argv)
return 0;
}

[Simon Sobisch]

You seem to want to create something that is callable from COBOL; in this case you want to add an extern C declaration as well.

The WinMain comes from your command line options - change wMain to WinMain - but again, if you want this to be called by GnuCOBOL you don't want that at all but use -shared (and likely drop -mwindows) to create a shared loadable object. And if you don't want that to be named a.out , then add -o create_integer_string.dll (or -o myhelper.dll which you then place into COB_PRE_LOAD.

... and you likely want to tell the linker to keep all elements (the default is to drop all unused functions and references, which are nearly all of your -l options).

[J McNamara]

Hey Simon,

that was awesome..

I found a guide to learn about calling c from cobol from ron normal.

I will give that a read.

I could have got this earlier today but I am not that good with all the C and mingw stuff so this is a huge help and I am sure with the guide I got mentioned below I will get there now.

thank you so much. I better save these notes in my notetaking app and back them up.

BTW an excellent Happy New Year to you Simon!

thanks,
jim

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