Conditional derivation from base class based on preprocessor ifdef and ifndef

[miteshpandey]

In our application we have the option of using color management or not. We are using a special library for color management.

This is controlled by preprocessor definitions.

#ifdef COLOR_MANAGEMENT

#ifndef COLOR_MANAGEMENT

Our application should be compilable and build if COLOR_MANAGEMENT is not defined and the corresponding source not included.

I have created a wrapper class to include this color management functionality.

Now other classes can be derived from this wrapper class if they wish to provide color management functionality.

But if COLOR_MANAGEMENT is not defined it would be useless to derive from this wrapper base class. So I need some kind of conditional inclusion of base class. But I think this is not possible.

I think templates could be the solution. But I am not sure. Could you all please suggest how I should be approaching this problem?

Instead of deriving from the wrapper class. I could just embed the wrapper class.

#ifdef COLOR_MANAGEMENT
#include "CMWrapper.h"
#endif

class MyClass
{
#ifdef COLOR_MANAGEMENT
     CMWrapper m_ColorMgntWrapper
#endif
};

But I don't like this solution.

So can templates rescue me. If yes then how I go about using it in my case?

Thanks


Please help.

[zerver]

Isn't this what you are looking for?

class MyClass
#ifdef COLOR_MANAGEMENT
     : public CMWrapper
#endif
{
};

[miteshpandey]

Thanks zerver didn't know if that was allowed

[cilu]

Everything that expands to valid C++ code is allowed with preprocessor directives.