avoid #define

[Vetzo]

Hello Forum,

I have class with the function "GetMessage()".

MyClass* objMyClass;
objMyClass = new MyClass;
objMyClass->GetMessage();

But when I call this function, the compiler (MVS) thinks that it is a macro from WinUser.h:

#define GetMessage GetMessageA

How do I tell the compiler to use the function?

Thank you.

[Ganado]

Welp, congrats you've ran into one of the atrocious issues with using macros (It's not your fault, it's Microsoft's fault).

Are you #including <windows.h> (or <winuser.h>) somewhere before you define either your class or your function call? First step would be to avoid #including <windows.h> in that file, unless you have to.

If you can't avoid that, try doing


#ifdef GetMessage
#undef GetMessage
#endif

before any reference to your "GetMessage" function.

See also:
https://stackoverflow.com/questions/2321713/how-do-i-avoid-name-collision-with-macros-defined-in-windows-header-files

If none of that works, you might just need to change your side of the code to conform to Microsoft's code (don't name something as a macro that already exists).

[jonnin]

Other ideas..

rename your function if possible.
you can also try a namespace on yours (possibly, the classname:: is good enough?)
you can also add a bogus parameter to yours (int x = 0) to see if that is good enough to allow an overload

probably some other tricks too.

[Vetzo]

Yes, I need the windows.h stuff.
undefining their stuff doesn't sound desirable. Either I use windows.h or not.
I already have a namespace for my code, but that doesn't seem to matter.

objMyClass->GetMessage(); // Where goes the namespace?
objMyClass->MyClass::GetMessage(); // Doesn't work.

Hmm, seems renaming my function is the best option.

Thanks.