Question

I am having a few problems with using codegen (via the gui interface).

I have successfully built a very simple c based .exe program based on the following two files.

coderand.m

function r = coderand() %#codegen
r = rand();

main.c

#include <stdio.h>
#include <stdlib.h>
#include "coderand.h"
int main()
{
  printf("coderand=%g\n", coderand());
  return 0;
}

If I now try and change out main.c for the same code in a main.cpp,

main.cpp

#include <stdio.h>
#include <stdlib.h>
#include "coderand.h"

void main(int argc, char **argv)
{
  printf("coderand=%g\n", coderand());
}

I get the following compile errors.

main.obj : error LNK2019: unresolved external symbol "double __cdecl coderand(void)" (?coderand@@YANXZ) referenced in function _main 25 F:\CoderTest\coderand.exe : fatal error LNK1120: 1 unresolved externals

Any help much appreciated.

Edit:- Solved by myself…

For those suffering the same problem…

Coder -> More Settings -> All Settings -> Advanced -> Language..change C to C++

Answer 1

C++ can call C functions without difficulty, you just have to let the compiler know that the C calling convention applies to this function, like so:

extern "C" {
#  include "coderand.h"
}