codegen:- Problems when attempting to build a c++ based .exe rather than c?

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.

.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

I assume it is because I am still building c code. What option do I have to change to fix this?

Answer 1

[Kaustubha Govind]

You probably need to add a extern "C" { } block around the declaration for coderand() in coderand.h, so that the C++ compiler doesn't use C++ style linkage.

Or try:

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

Answer 2

[Adam Hartshorne]

I have found the solution...As suspected it was due to the codegen being set to build c rather than c++ code.

For those suffering a similar problem, you have to go to

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