C ++ dll in C program

Question

I would like to create a dll library from C ++ code and use it in a C program . I would like to export only one function:

GLboolean load_obj (const char *filename, GLuint &object_list);

Library header file:

#ifndef __OBJ__H__
#define __OBJ__H__

#include <windows.h>  
#include <GL/gl.h>
#include <GL/glext.h>
#include <GL/glu.h>
#include <GL/glut.h>

#if defined DLL_EXPORT
#define DECLDIR __declspec(dllexport)
#else
#define DECLDIR __declspec(dllimport)
#endif

extern "C" GLboolean load_obj (const char *filename, GLuint &object_list);

#endif // __3DS__H__

in .cpp (in the library project) is also declared as:

extern "C" GLboolean load_obj (const char *filename, GLuint &object_list)
{
 code...
}

The .lib file is added to the VS project options (Linker / Input / Additional dependencies) .. dll is in the folder where the .exe is located. When I compile the C project - error:

Error   1   error C2059: syntax error : 'string'    

This is the part of "extern" C "" in the header file.

I tried changing the header file:

extern GLboolean load_obj (const char *filename, GLuint &object_list);

then

Error   1   error C2143: syntax error : missing ')' before '&'  
Error   2   error C2143: syntax error : missing '{' before '&'  
Error   3   error C2059: syntax error : '&' 
Error   4   error C2059: syntax error : ')' 

and even when I changed & to *:

Error   6   error LNK2019: unresolved external symbol _load_obj referenced in function _main    main.obj    

I do not know why this is wrong .. lib.h and .dll are added correctly.

Answer 1

"GLuint &object_list" " GLuint ". C . .

// declaration
extern "C" GLboolean load_obj (const char *filename, GLuint *object_list);

// definition
GLboolean load_obj (const char *filename, GLuint *object_list)
{
    code...
}

Answer 2

C , .

, extern "C". C .

, - :

#ifdef __cplusplus
    extern "C" {
#endif

/* extern "C" stuff */

#ifdef __cplusplus
    }
#endif

C, __cplusplus .