unresolved external symbol "int __cdecl _.." between C and Cpp file

[leKoxn]

Hi all, I am receiving a

"error LNK2019: unresolved external symbol "int __cdecl _function(...)" error while trying to compile the following files:

main.cpp
--------------------------------------------
#include "function.h"


int main()
{

function(0, 0);

return 0;
}

---------------------------------------------


function.h
--------------------------------------------

#ifndef FNC_H
#define FNC_H

extern void function(int a, int b);

#endif
---------------------------------------------


function.c
--------------------------------------------

#include "function.h"

void function(int a, int b);
{
// do something here
}
---------------------------------------------



Seems like the program cannot find the function's definition. Why is that?
Am I missing something with the association .h -> .c ?

Please give me suggestions

[PredicateNormative]

Remove the extern keyword from your function.h header file so that it becomes:

#ifndef FNC_H
#define FNC_H

void function(int a, int b);

#endif

[leKoxn]

That does not solve my problem and I still get the same error.

If I rename the file from .c to .cpp, I obtain something like 400 errors (obviously I made simple here the code for readability purpose) for syntax overloading stupid things..

I don't know how to solve really

[PredicateNormative]

Sorry, I didn't notice that it was a main.cpp and not a main.c. The problem is that you basically need to put the function(a,b) declaration in your function.h file within an extern "C" statement, with the caveate that you will only want that extern "C" statement to be seen in the compilation with the main.cpp file, but not with the compilation of the function.c file.

Thus the solution is to rewrite your function.h file as follows:

#ifndef FNC_H
#define FNC_H

#ifdef __cplusplus
extern "C" 
{
#endif

void function(int a, int b);

#ifdef __cplusplus
}
#endif

#endif

Also, in the example you supplied you have a spurious ; at the end of your function signature in function.c.

[leKoxn]

You was right, thank you!