Can there be anything between keyword 'class' and class name in c++?

Question

I encountered a code in c++ where class has been defined like :

class MACRO class_name
{
     public :

     private :

}

I'm sorry to hear that. I'd advise staying away from...wherever you found that. — Jerry Coffin, Aug 03 '15 at 05:21
Yep, you can do it using #define: http://stackoverflow.com/questions/3563783/class-name-macro But it smells bad :) — Artem Kulikov, Aug 03 '15 at 05:23

score 8 · Answer 1 · answered Aug 03 '15 at 05:30

In standard C++11 and later, there can be attributes between class and the class name. It is also possible (even more likely, perhaps) that the macro expands to non-standard attribute syntax supported by the particular compiler that is being used to compile the code.

Melkon · Accepted Answer · 2015-08-03T07:14:28.513

4

If you saw it on a Windows code, this is probably a macro which determine if you want to export or import the given class.

It's very common if you are dealing with dll-s.

So, this macro is probably something like this:

#ifdef  PROJECTNAME_EXPORTS

#define MACROBEFORECLASSNAME __declspec(dllexport)
#else
#define MACROBEFORECLASSNAME __declspec(dllimport)
#endif

If you compile the dll, the PROJECTNAME_EXPORTS preprocessor definition should be defined, so the compiler will export the given class. If you compile a project which is just using the given dll, the ...EXPORTS won't be defined, so the compiler will import the given class.

edited Aug 03 '15 at 07:14

answered Aug 03 '15 at 06:55

Melkon

408
4
12

1

You are right, i am talking about windows, i edit the post. :) – Melkon Aug 03 '15 at 07:13
1

On MSVC, there's also `__declspec(novtable)`: https://msdn.microsoft.com/en-us/library/k13k85ky.aspx – peterchen Aug 03 '15 at 07:21

Can there be anything between keyword 'class' and class name in c++?

2 Answers2