Re: Linking error in mixed code

From:

"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 23 Jul 2008 10:30:52 -0700

Message-ID:

<ufnfdnO7IHA.3512@TK2MSFTNGP03.phx.gbl>

<swtbase@gmail.com> wrote in message
news:c950016b-835b-459f-bf24-571dde854240@y38g2000hsy.googlegroups.com...

Thanks for all the help. Ok here's what I tried:

#pragma unmanaged
#include <windows.h>
namespace UnManaged
{
     ...

     // My subclassed winproc
     extern "C" long __cdecl UnManagedWinProc(HWND hWnd, unsigned int
uMsg, unsigned int wParam, long lParam)
     {
         ...
         if(uMsg == WM_CLIPBOARDCHANGED)
                  // HERE I MUST CALL 'ClipBoard_ContentChanged'
FUNCTION IN 'MyApp' NAMESPACE
        ....
     }
}

#pragma managed
namespace MyApp
{
        ....
        using namespace UnManaged;

        ....

       public: void ClipBoard_ContentChanged(void){...};
}

Here, namespace 'MyApp' is defined after namespace 'UnManaged'. So,
how can I call a function in namespace defined afterwards from a
function in namespace before it?

You can't. The C++ compiler still works the same way - you can't have
unknown forward references. You'll need to rearrange your code so the
compiler knows the namespaces and types where it needs to.

You could maybe move the MyApp namespace stuff into its own .h file and
include that file above the UnManaged namespace code.
If you run into a circular reference problem, you may need to adjust the
design a bit.

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++