the error is :

Error: undefined identifier RegisterClassExW, did you mean function RegisterClassExA?

No I didn't mean that.

So how to import winapi functions ?

Am 27.01.2013 18:45, schrieb rsk82:
> the error is :
>
> Error: undefined identifier RegisterClassExW, did you mean function
> RegisterClassExA?
>
> No I didn't mean that.
>
> So how to import winapi functions ?

extern(Windows) <insert function definition here>

On Sunday, 27 January 2013 at 17:51:40 UTC, Benjamin Thaut wrote:
> extern(Windows) <insert function definition here>

I am not sure what I was supposed to do, so I did this:

extern(Windows) ATOM RegisterClassExW(const WNDCLASSEXW *lpwcx);
ATOM class_atom = RegisterClassExW(&wc);

and got linker error:

OPTLINK (R) for Win32  Release 8.00.12
Copyright (C) Digital Mars 1989-2010  All rights reserved.
http://www.digitalmars.com/ctg/optlink.html
test.obj(test)
 Error 42: Symbol Undefined __D4test8doWindow6__ctorMFZC4test8doWindow16RegisterClassExWWxPS4test8doWindow6__ctorMFZC4test8doWindow11WNDCLASSEXWZt@4
--- errorlevel 1

Am 27.01.2013 19:01, schrieb rsk82:
> On Sunday, 27 January 2013 at 17:51:40 UTC, Benjamin Thaut wrote:
>> extern(Windows) <insert function definition here>
>
> I am not sure what I was supposed to do, so I did this:
>
> extern(Windows) ATOM RegisterClassExW(const WNDCLASSEXW *lpwcx);
> ATOM class_atom = RegisterClassExW(&wc);
>
> and got linker error:
>
> OPTLINK (R) for Win32  Release 8.00.12
> Copyright (C) Digital Mars 1989-2010  All rights reserved.
> http://www.digitalmars.com/ctg/optlink.html
> test.obj(test)
>   Error 42: Symbol Undefined
> __D4test8doWindow6__ctorMFZC4test8doWindow16RegisterClassExWWxPS4test8doWindow6__ctorMFZC4test8doWindow11WNDCLASSEXWZt@4
>
> --- errorlevel 1

Did you link against User32.lib?
I also recommend that you use VisualD it will give you "pretty" linker error messages.

Kind Regards
Ingrater

On Sunday, 27 January 2013 at 18:01:38 UTC, rsk82 wrote:
> On Sunday, 27 January 2013 at 17:51:40 UTC, Benjamin Thaut wrote:
>> extern(Windows) <insert function definition here>
>
> I am not sure what I was supposed to do, so I did this:
>
> extern(Windows) ATOM RegisterClassExW(const WNDCLASSEXW *lpwcx);

This must be declared at module level (not inside a function).

> ATOM class_atom = RegisterClassExW(&wc);
>
> and got linker error:
>
> OPTLINK (R) for Win32  Release 8.00.12
> Copyright (C) Digital Mars 1989-2010  All rights reserved.
> http://www.digitalmars.com/ctg/optlink.html
> test.obj(test)
>  Error 42: Symbol Undefined __D4test8doWindow6__ctorMFZC4test8doWindow16RegisterClassExWWxPS4test8doWindow6__ctorMFZC4test8doWindow11WNDCLASSEXWZt@4
> --- errorlevel 1

On Sunday, 27 January 2013 at 18:26:04 UTC, John Chapman wrote:
> This must be declared at module level (not inside a function).

Ok, I've put it into module, linked in the module
pragma(lib, "user32.lib");
and
pragma(lib, "gdi32.lib");

all this works until I put

extern(Windows) ATOM RegisterClassExW(const WNDCLASSEXW *lpwcx);

on line 30, then I get as if this was a code not a new function import:

.\mod\myModule.d(30): Error: undefined identifier WNDCLASSEXW, did you mean struct WNDCLASSEXA?

On Sunday, 27 January 2013 at 17:51:40 UTC, Benjamin Thaut wrote:
> extern(Windows) <insert function definition here>

I don't know If that what you meant but this works *inside* the code:

extern(Windows)
ATOM class_atom = RegisterClassExW(&wc);

On Sunday, 27 January 2013 at 18:58:59 UTC, rsk82 wrote:
> On Sunday, 27 January 2013 at 18:26:04 UTC, John Chapman wrote:
>> This must be declared at module level (not inside a function).
>
> Ok, I've put it into module, linked in the module
> pragma(lib, "user32.lib");
> and
> pragma(lib, "gdi32.lib");
>
> all this works until I put
>
> extern(Windows) ATOM RegisterClassExW(const WNDCLASSEXW *lpwcx);
>
> on line 30, then I get as if this was a code not a new function import:
>
> .\mod\myModule.d(30): Error: undefined identifier WNDCLASSEXW, did you mean struct WNDCLASSEXA?

Because WNDCLASSEXW is not defined. So define it above RegisterClassExW.

struct WNDCLASSEXW {
  UINT      cbSize = WNDCLASSEXW.sizeof;
  UINT      style;
  WNDPROC   lpfnWndProc;
  int       cbClsExtra;
  int       cbWndExtra;
  HINSTANCE hInstance;
  HICON     hIcon;
  HCURSOR   hCursor;
  HBRUSH    hbrBackground;
  LPCTSTR   lpszMenuName;
  LPCTSTR   lpszClassName;
  HICON     hIconSm;
}

On Sunday, 27 January 2013 at 19:25:28 UTC, rsk82 wrote:
> extern(Windows)
> ATOM class_atom = RegisterClassExW(&wc);

No, I'm wrong, now the compiler ignores the class that I put in my module, I can write every nonsense that comes to my mind and it compiles. But if I put extern outside of the class then it shows error.

On Sunday, 27 January 2013 at 19:29:03 UTC, John Chapman wrote:
> On Sunday, 27 January 2013 at 18:58:59 UTC, rsk82 wrote:
>> On Sunday, 27 January 2013 at 18:26:04 UTC, John Chapman wrote:
>>> This must be declared at module level (not inside a function).
>>
>> Ok, I've put it into module, linked in the module
>> pragma(lib, "user32.lib");
>> and
>> pragma(lib, "gdi32.lib");
>>
>> all this works until I put
>>
>> extern(Windows) ATOM RegisterClassExW(const WNDCLASSEXW *lpwcx);
>>
>> on line 30, then I get as if this was a code not a new function import:
>>
>> .\mod\myModule.d(30): Error: undefined identifier WNDCLASSEXW, did you mean struct WNDCLASSEXA?
>
> Because WNDCLASSEXW is not defined. So define it above RegisterClassExW.
>
> struct WNDCLASSEXW {
>   UINT      cbSize = WNDCLASSEXW.sizeof;
>   UINT      style;
>   WNDPROC   lpfnWndProc;
>   int       cbClsExtra;
>   int       cbWndExtra;
>   HINSTANCE hInstance;
>   HICON     hIcon;
>   HCURSOR   hCursor;
>   HBRUSH    hbrBackground;
>   LPCTSTR   lpszMenuName;
>   LPCTSTR   lpszClassName;
>   HICON     hIconSm;
> }

Actually, replace "LPCTSTR" above with "LPCWSTR".