Re: Linking error in mixed code

From:
"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nospam>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 22 Jul 2008 10:06:45 -0700
Message-ID:
<OU#kT1B7IHA.1428@TK2MSFTNGP06.phx.gbl>
<swtbase@gmail.com> wrote in message
news:2dd7ebf1-48ce-408e-a455-752e9b43e865@2g2000hsn.googlegroups.com...

Hi all,
I have a .NET application which needs to use some Win APIs. I set the
linker option (of VC++ .NET 2008 Express) to '\clr' to use mixed code
and added the following line of code:

...
#pragma unmanaged
namespace UnManagedFuncs
{
using namespace System::Runtime::InteropServices;

[DllImport("user32", EntryPoint = "SetClipboardViewer", CharSet =
CharSet::Unicode)]
extern "C" long __cdecl SetClipboardViewer(void* hWnd);

[DllImport("user32", EntryPoint = "SetWindowLong", CharSet =
CharSet::Unicode)]
extern "C" long __cdecl SetWindowLongW(void* hWnd, int nIndex, long
dwNewLong);

[DllImport("user32", EntryPoint = "CallWindowProc", CharSet =
CharSet::Unicode)]
extern "C" long __cdecl CallWindowProcW(long* lpPrevWndFunc, void*
hWnd, unsigned int uMsg, unsigned int wParam, long lParam );

...
}

#pragma managed
namespace MyApp
{
                 ...
                 private: System::Void frmMain_Load(System::Object^
sender, System::EventArgs^ e)
{
              // Register this window to receive 'clipboard contents
changed' event
UnManagedFuncs::SetClipboardViewer((void*)this->Handle);

                               UnManagedFuncs::HookWindow((void*)this-

Handle);

               }
}

I get the following linker errors:
ScratchBook.obj : error LNK2019: unresolved external symbol
_CallWindowProcW referenced in function _UnManagedWinProc
ScratchBook.obj : error LNK2019: unresolved external symbol
_SetWindowLongW referenced in function "void __cdecl
UnManagedFuncs::HookWindow(void *)" (?
HookWindow@UnManagedFuncs@@YAXPAX@Z)

What is wrong?


Corrections for my last post...

[DllImport("user32.dll", CharSet = CharSet::Unicode)]
extern IntPtr SetClipboardViewer(IntPtr hWnd);

[DllImport("user32.dll", CharSet = CharSet::Unicode)]
extern long SetWindowLongW(IntPtr hWnd, int nIndex, long dwNewLong);

[DllImport("user32.dll", CharSet = CharSet::Unicode)]
extern IntPtr CallWindowProcW(IntPtr lpPrevWndFunc, IntPtr hWnd, unsigned
int uMsg, IntPtr wParam, IntPtr lParam );

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++
 

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