Re: Building multiple backends on on same system

[Matthias Clasen <matthias clasen gmail com>]

On Mon, Dec 13, 2010 at 4:39 AM, Benjamin Otte <otte gnome org> wrote:
> What I'd do is put all the headers in the same directory, but add a
> #ifdef GDK_WINDOWING_X11 to the header and then put
> -DGDK_WINDOWING_X11 into gtk+-3.0-x11.pc That way we avoid lots of
> different include directories and IMO makes it easier to look for
> header files in one's installation.
> There's also the question of what we should do when someone includes
> gdkx.h without having GDK_WINDOWING_X11 defined. Do nothing or #error
> "You must add gtk+-3.0-x11 to your pkgconfig flags." The first one has
> the benefit of not requiring lots of ifdefs for the include files, the
> second makes the error output way better (because you don't have
> missing function definition complaints from gcc, but useful output). I
> vote or the second btw.

That would really change the meaning of the WINDOWING  define though.
So far, it indicates that the installed library supports a windowing
system. With your idea, it would also be used to indicate that the
application wants to use windowing system specific functions. I think
it is better to keep these separate.