Re: [Mingw-users] vtables incompatible with visual studio compiler

[Roman W. <rom...@gm...>]

> If it's a C++ header file then probably it is subject to all kinds of
> undocumented grey areas in the standard,

I find many header directives making things compatible. Like:
"#pragma pack(push,1)" __stdcall "extern C", abstract C++ classes
(only pure virtuals methods)

> which means that future versions
> of Visual Studio might well be incompatible with it, as well as all other
> C++ compilers (MinGW, Watcom, Borland...)

I do not believe Microsoft guys would make things incompatible to them
self, they used to follow their own history.
I feel the spirit of MinGW and gcc-cross-compilation is to give an
alternative, so they probably will not remove to much of
compatibility.

> Is it possible for you to give the overloaded methods unique names to work
> around this? (so that they're no longer overloaded)

Yes:

class Vtable {
#ifdef __GNU__
 virtual void Overloaded(Vtable&) = 0;
 virtual void Overloaded(int) = 0;
#elif _MSC_VER  //microsoft compiler
 virtual void Overloaded(int) = 0;
 virtual void Overloaded(Vtable&) = 0;
#endif
 virtual void Other() = 0;
};

generates same virtual tables as

class Vtable {
//order used by gcc
 virtual void Overloaded1(Vtable&) = 0;
 virtual void Overloaded2(int) = 0;
 virtual void Other() = 0;
};

for both MinGw and visual studio express

Thank you much, it makes things simpler and generaly works for
"preprocessor macro" i was looking for.
Even if it works only due to grey areas of vtable generation.