I have a simple DLL that I am trying to compile in VS2010 Express.

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Asked: June 4, 20262026-06-04T18:01:07+00:00 2026-06-04T18:01:07+00:00

I have a simple DLL that I am trying to compile in VS2010 Express.

0

I have a simple DLL that I am trying to compile in VS2010 Express.
The code for the DLL is as follows:

#pragma comment(linker, "/EXPORT:PlusOne=_PlusOne@4")

#include <windows.h>
#include <commctrl.h>

extern "C"  __declspec(dllexport) int PlusOne(int inNum)
{
    inNum++;
    return inNum;
};

extern "C"  __declspec(dllexport) LRESULT CALLBACK OwnerDrawButtonProc(HWND hWnd, UINT uMsg, WPARAM wParam,
                               LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
//further processing will go here
   return DefSubclassProc(hWnd, uMsg, wParam, lParam);
};

__stdcall is selected in the project options

The plusOne function on its own compiles fine but the second function does not.

DefSubclassProc is declared in commctrl.h but I get an error on the function, full error text including the libraries searched (which includes commdlg32 where this function lives) is below:

1>  Searching libraries
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\winmm.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\kernel32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\user32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\gdi32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\winspool.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\comdlg32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\advapi32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\shell32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\ole32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\oleaut32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\uuid.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\odbc32.lib:
1>      Searching C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\lib\odbccp32.lib:
1>      Searching c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\lib\MSVCRT.lib:
1>      Searching c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\lib\OLDNAMES.lib:
1>  
1>  Finished searching libraries
1>dlltest.obj : error LNK2001: unresolved external symbol _DefSubclassProc@16
1>s:\documents\my documents\visual studio 2010\Projects\dlltest\Release\dlltest.dll : fatal error     LNK1120: 1 unresolved externals

It looks like it can’t find the function but the library and header are present so I don’t understand why.

As a small aside the motivation for the code is that I am subclassing a window in vba, but having the windowprocedure in vba is very unstable so I want to try and move it into a dll.

Please help me understand what is going wrong here.