getProcAddress - NULL is returned - c++

Question

I have the following code:
//mydll.cpp
#include <Windows.h>
#include <io.h>
#define STDOUT_FILEDESC 1
class MYSTDOUT {
bool shouldClose;
bool isBuffered;
public:
MYSTDOUT(bool buf = true, bool cl = true)
: isBuffered(buf),
shouldClose(cl)
{}
~MYSTDOUT() {
if (shouldClose) {
close(STDOUT_FILEDESC);
}
}
};
__declspec(dllexport) void* mydll_init_stdout()
{
static MYSTDOUT outs;
return &outs;
}
//test_dll.cpp
#include <stdio.h>
#include <stdlib.h>
#include <Windows.h>
#include <io.h>
typedef void* (__cdecl *MYPROC)(void);
int main(void)
{
int fd;
void *pstdout;
MYPROC init_stdout;
HMODULE handle = LoadLibrary(TEXT("mydll.dll"));
init_stdout = (MYPROC)GetProcAddress(handle,"mydll_init_stdout");//NULL
FreeLibrary((HMODULE) handle);
return 0;
}
I get that init_stdout is NULL.What could be a problem?
handle is OK(Not NULL)
Thank you

Answer 1

That is due to name-mangling.
You need to wrap the exported function in extern "C" as:
extern "C"
{
__declspec(dllexport) void* mydll_init_stdout()
{
static MYSTDOUT outs;
return &outs;
}
}

Answer 2

Have a check in Dependency Walker, or dumpbin /exports and you will see that mydll_init_stdout has been exported with a mangled C++ name. That's why the GetProcAddress call fails.
Use extern "C" to stop mangling.
extern "C"
{
__declspec(dllexport) void* mydll_init_stdout()
{
static MYSTDOUT outs;
return &outs;
}
}