Can someone help me with this:
I have a library which I try to import from D
//funcs.lib
//windows includes...
HWND hwnd;
int setHWND(HWND extHwnd){
	hwnd = extHwnd;
	return 0;
}

//main.d
pragma(lib, "gdi32.lib");
import core.runtime;
import core.sys.windows.windows;
extern (C++) {
	int setHWND(HWND hwnd);
}
int main(int argc, char **argv) {
//windows initializers
	setHWND(hwnd);
	return 0;
}

but when I try to import that function this comes:
   Error 42: Symbol Undefined ?setHWND@@YAHPAX@Z (int cdecl
setHWND(void *))
--- errorlevel 1

it seems like I cannot use HWND directly.

On Sun, 30 Jun 2013 20:24:17 +0200, shuji <cravstar@hotmail.com> wrote:


> int setHWND(HWND extHwnd){
> 	hwnd = extHwnd;
> 	return 0;
> }
And:

> extern (C++) {
> 	int setHWND(HWND hwnd);
> }


See how these are different? One of them is an extern (C++) function, the other is a D function.

In other words, this should work:

//funcs.lib
//windows includes...
HWND hwnd;
extern (C++) { // This line!
int setHWND(HWND extHwnd){
	hwnd = extHwnd;
	return 0;
}
}

//main.d
pragma(lib, "gdi32.lib");
import core.runtime;
import core.sys.windows.windows;
extern (C++) {
	int setHWND(HWND hwnd);
}
int main(int argc, char **argv) {
//windows initializers
	setHWND(hwnd);
	return 0;
}



-- 
Simen

this code is in a .cpp file
//funcs.lib
//windows includes...
HWND hwnd;
int setHWND(HWND extHwnd){
	hwnd = extHwnd;
	return 0;
}

So im trying to import from D like this. I dont think I can implement this line in C++
extern (C++) {}

On Sunday, 30 June 2013 at 19:03:13 UTC, shuji wrote:
> this code is in a .cpp file
> //funcs.lib
> //windows includes...
> HWND hwnd;
> int setHWND(HWND extHwnd){
> 	hwnd = extHwnd;
> 	return 0;
> }
>
> So im trying to import from D like this. I dont think I can implement this line in C++
> extern (C++) {}

I'm probably the most unqualified person to offer help but are you sure you are linking with funcs.lib (assuming setHWND is defined there)

On Sunday, 30 June 2013 at 20:04:12 UTC, Anthony Goins wrote:
> On Sunday, 30 June 2013 at 19:03:13 UTC, shuji wrote:
>> this code is in a .cpp file
>> //funcs.lib
>> //windows includes...
>> HWND hwnd;
>> int setHWND(HWND extHwnd){
>> 	hwnd = extHwnd;
>> 	return 0;
>> }
>>
>> So im trying to import from D like this. I dont think I can implement this line in C++
>> extern (C++) {}
>
> I'm probably the most unqualified person to offer help but are you sure you are linking with funcs.lib (assuming setHWND is defined there)

yes, i have called other functions in the same file correctly.

PD I can call a function with void* as receiving paremeter:
//main.d
extern (C++) {
	int setHWND(void* ehwnd);
}
//mylib.cpp
int setmyHWND(void* exthwnd){
	hwnd = (HWND)exthwnd;
	return 0;
}
and then cast on C++ to HWND, but I think it would be better to send the parameter correctly as HWND.

Am 30.06.2013 22:20, schrieb shuji:
> On Sunday, 30 June 2013 at 20:04:12 UTC, Anthony Goins wrote:
>> On Sunday, 30 June 2013 at 19:03:13 UTC, shuji wrote:
>>> this code is in a .cpp file
>>> //funcs.lib
>>> //windows includes...
>>> HWND hwnd;
>>> int setHWND(HWND extHwnd){
>>>     hwnd = extHwnd;
>>>     return 0;
>>> }
>>>
>>> So im trying to import from D like this. I dont think I can implement
>>> this line in C++
>>> extern (C++) {}
>>
>> I'm probably the most unqualified person to offer help but are you sure you are linking with funcs.lib (assuming setHWND is defined there)
> 
> yes, i have called other functions in the same file correctly.
> 
> PD I can call a function with void* as receiving paremeter:
> //main.d
> extern (C++) {
>     int setHWND(void* ehwnd);
> }
> //mylib.cpp
> int setmyHWND(void* exthwnd){
>     hwnd = (HWND)exthwnd;
>     return 0;
> }
> and then cast on C++ to HWND, but I think it would be better to send the
> parameter correctly as HWND.

make sure the HWND parameter is on both "sides" the same (it has to get mangled correctly!). I don't know if HWND is an opaque struct, if it is, this might get you into trouble.

--- Cut here, I looked into core.sys.windows.windows:


---
alias void *HANDLE;
alias HANDLE HWND;
---

That is the problem, on the C++-Side HWND is not of type void* hence it gets mangled differently, you need to get DMD mangle it the same as the C++ compiler does...

The problem is (I just looked it up) HWND is *basically* void*

All typedefs:
PVOID = void*
HANDLE = PVOID
HWND = HANDLE

So you have to "emulate" a typedef to get the correct mangling... Maybe start messing arround with structs?

struct HWND;
etc.


Maybe you could also try to use the deprecated "typedef" in D. Neither of these soloutions are really great. I would consider this another bug on the extern(C++) list.