Using the #define macro to standardize class declaration - c++

Question

I'm building a C++ DLL for one of my projects. I am trying to standardize the way that are class are defined. So instead of each time writing:
class __declspec(dllexport) ClassName
I'm building a #define macro to ease this process:
#define CLASS( cName ) class __declspec(dllexport) cName
But, when I'm using it, it gives me the following error:
Error: Expected a ';'
I know you can use a #define macro to define an entire class creation, but can it be used to define only the "class header" ?
Thanks,
Keep in mind that I'm trying to do so because we are going to deal with hundreds of classes, so these kinds of "automation" would be most helpful :)
EDIT:
example:
#define CLASS( nClass ) class __declspec(dllexport) nClass
CLASS( APTest )
{ // Here is the error of missing ';'
public:
APTest();
};

Answer 1

Don't do this.
C++ has already been standardized!
If you ever expect other people to read your code then just write it in conventional C++, not some homecooked dialect that looks different. Get used to the proper C++ syntax, it will make it easier to read other people's C++ code.
One thing that does make sense is to simplify the __declspec part, which you can do like this:
#ifdef _WIN32
#define DLLEXPORT __declspec(dllexport)
#else
#define DLLEXPORT
#endif
class DLLEXPORT APTest
{
// ...
};
You're really not making your life any simpler by writing CLASS( APTest ) and you make it harder for others to understand. Just say no.

Answer 2

There is a better way than #Wakely. Do it like this:
#ifdef MYLIB_DLL
#ifndef MYLIB_IFACE
#ifdef MYLIB_IFACE_EXPORT
#define MYLIB_IFACE _declspec( dllexport )
#else // !MYLIB_IFACE_EXPORT
#define MYLIB_IFACE _declspec( dllimport )
#endif // !MYLIB_IFACE_EXPORT
#endif // !MYLIB_IFACE
#else // !MYLIB_DLL
#ifndef MYLIB_IFACE
#define MYLIB_IFACE
#endif // !MYLIB_IFACE
Put a block like that in a header that is used by every file in your dll, and in the public header for your dll.
Every symbol that should be exported from your dll gets tagged like this:
class MYLIB_IFACE MyClass
{
};
void MYLIB_IFACE myFunc();
Then in every .cpp file in your dll the first line should be:
#define MYLIB_IFACE_EXPORT
If you do this, then it will build just fine on POSIX systems that don't use dllexport/dllimport. To build a dll version of your lib you define MYLIB_DLL. ( you can do this in the compiler's flags so it can be controlled from your build system )
To build a static version of your lib, don't define MYLIB_DLL.
#Update:
You can extend this to support GCC visilibity like this:
#ifdef WIN32
#define KX_SYMBOL_EXPORT _declspec( dllexport )
#define KX_SYMBOL_IMPORT _declspec( dllimport )
#else // GCC
#define KX_SYMBOL_EXPORT __attribute__(( visibility ("default")))
#define KX_SYMBOL_IMPORT
#endif
#ifdef KX_DLL
#ifndef KX_IFACE
#ifdef KX_IFACE_EXPORT
#define KX_IFACE KX_SYMBOL_EXPORT
#else // !KX_IFACE_EXPORT
#define KX_IFACE KX_SYMBOL_IMPORT
#endif // !KX_IFACE_EXPORT
#endif // !KX_IFACE
#else // !KX_DLL
#ifndef KX_IFACE
#define KX_IFACE
#endif // !KX_IFACE
#endif // !KX_DLL
I remove the GCC bit in the first example for simplicity. But this is how a really do it. #Wakely is so right.