Created attachment 1120 [details]
renames SDL_Event's "generic" field to "common", for future C++/CX compatibility

Hi,

I just wanted to give you all a heads-up regarding a possible incompatibility for any future versions of SDL that support WinRT, or one of the platforms it is based on.  I've been doing work on an unofficial port of SDL 2.x to WinRT (at http://bitbucket.org/davidludwig/sdl), and found a bug that, if SDL were ever to support WinRT, or one of the platforms it is based on (Windows Phone 8 being one), it may prevent SDL's public headers from being compiled without hacks.  The issue was found while doing a merge of my own fork (of SDL 2.x) with the latest code from hg.libsdl.org/SDL.

The issue is that a recent commit, http://hg.libsdl.org/SDL/rev/4de584a3a027, added a field to SDL_Event, "generic", which can cause SDL_event.h to not be compile-able.  The word "generic" is reserved in a new, Microsoft-specific, C++ extension called C++/CX, which is used to help build WinRT components.  More info on the keyword is available at http://msdn.microsoft.com/en-us/library/windows/apps/hh755792.aspx.  The C++/CX extension is optional for WinRT development, and can be turned off to allow SDL_event.h to compile.  Much of Microsoft's sample code and documentation for WinRT, however, does use the extension.

It is possible to work around the problem, however there are drawbacks.  Macros can be used to redefine 'generic', however this could make it difficult to use SDL_Event's new filed in C++/CX enabled code, in a cross-platform manner.  C++/CX can be disabled, however this would prevent much of Microsoft's sample code for WinRT from being used in the same files that use SDL, or at least make it difficult.

In case modifying SDL 2.x is an option, I've attached one possible patch that renames SDL_Event's "generic" field to "common".  The patch was not made against my own tree, and instead was made against an up-to-date copy of the official SDL 2.x HG sources (as of the changeset, http://hg.libsdl.org/SDL/rev/ab543a0ef80c).

This is the only language-level incompatibility I've seen so far (in compiling SDL's public headers with C++/CX).  I have run into a fair amount of other incompatibilities involved with porting SDL to WinRT, however most of those have been API related.  This is the only bug I've seen so far that has required any sort of change to the SDL public API.

Cheers, and good luck with the SDL 2.x update!