calling native function pointer in c++/cli

I have a native function inside a managed (c++/cli) mixed-mode library that calls a seperate native dll.

Here is the native function that initializes some function pointers using windows GetProcAdress:

//in header
static HMODULE hDll;
static void (*MYDLL_Func1)(void*);
static void (*MYDLL_Func2)(void);

int BeginDll()
{
    if (!hDll) {
        hDll= LoadLibraryHelper("mydll.dll");
        if (hDll) {
            MYDLL_Func1 = (LPVOID)GetProcAddress(hDll, "MYDLL_Func1");
            MYDLL_Func2 = (LPVOID)GetProcAddress(hDll, "MYDLL_Func2");

            if (!MYDLL_Func1||
                !MYDLL_Func2)
 开发者_如何转开发           {
                FreeLibrary(hDll); hDll= NULL;
            } else {
                Log("were good to go");
            }
        }
    }
    return (hDll!= NULL);
}

now I want to write a wrapper function that will call this function pointer, but in doing so I get an "AccessViolationException"

public ref struct Wrapper sealed abstract
{
    void ManagedFunc(IntPtr hwnd)
    {
        if (BeginDll())
        {
            MYDLL_Func1(reinterpret_cast<HWND>(hwnd.ToPointer));
            MYDLL_Func2();
        }
    }
}

I am not assuming I can call a function pointer in c++/cli code, I am simply wondering a correct way to do this. If I add the api dll's header file and call the functions implicitly, I run into the problem that if the native helper dll is not in the directory with the managed dll the application bombs after the first call. ("AccessViolationException")

MYDLL_Func1(reinterpret_cast<HWND>(hwnd.ToPointer));

should be

MYDLL_Func1(hwnd.ToPointer());

Casts are evil. Casting a member function to a data pointer is just wrong.

For some reason the correct answer was posted by Hans Passat but it is not available anymore, if anyone wants to know how this was fixed I'll sum it up:

the static declarations of the function pointers were causing each source file to have its own copy so they become the following in the declaration file

extern void (*MYDLL_Func1)(void*);

and in the source file

void (*MYDLL_Func1)(void*);

he also says to change the calling convention to _stdcall, but this is in a .C file but _cdecl compiles just fine.

I did however end up switching back to including the DLL's header file and calling functions implicitly. For some reason with this solution, I was getting a buffer overrun in my C# client when running outside of the debugger. Seeing as the problem did not exsist while trying to debug it, I reverted to a different solution. I suppose I just need to be careful to not include the DLL with my managed DLL and client.