Compiler Errors in atlwin.h

Question

When including atlwin.h from the Microsoft ATL libraries in Visual Studio 2013 building will result in numerous complier errors about undefined elements.

i.e.

#include <atlwin.h>
class MainWnd : public CWindowImpl<MainWnd>
{};

"CWindowImpl: base class is not defined" error.

or

HMONITOR is not defined

This does not occur when building using VS2010.

How can I fix that?

Answer 1

The problem is with the targeted version of windows in the stdafx.h file

from MSDN

Visual C++ no longer supports targeting Windows 95, Windows 98, Windows ME, or Windows NT. If your WINVER or _WIN32_WINNT macros are assigned to one of these versions of Windows, you must modify the macros. When you upgrade a project that was created by using an earlier version of Visual C++, you may see compilation errors related to the WINVER or _WIN32_WINNT macros if they are assigned to a version of Windows that is no longer supported.

So, changing

#ifndef WINVER  
#define WINVER 0x0400   
#endif

to

#ifndef WINVER  
#define WINVER 0x0500
#define _WIN32_WINNT 0x0500
#endif

corrects the build problem

Answer 2

CWindowImpl is defined in <atlwin.h>, so you need to include that. I don't know what the file atldwin.h that you're including is, but apparently it doesn't contain that class.

Edit: According to a comment below by CCondron, this is due to targeting versions of Windows no longer supported by Visual C++. To fix, add:

#define WINVER 0x0500 
#define _WIN32_WINNT 0x0500