Re: [Glsdk-devel] The use of anonymous structures

[Jason M. <ko...@gm...>]

Stefanos A. wrote:
> On Sun, Aug 24, 2008 at 6:31 AM, Branan Riley <br...@gm...> wrote:
>   
>>         Could be a different version of MSVC giving different
>>         warnings.
>>     
>
> Actually no, just stricter warnings (warning level 4, where the default
> is 3). GCC doesn't produce any warnings even with -Wall.
>
> However, please note that the anonymous union is *not* valid C89 (fails
> to compile with "gcc -ansi"). I'm not saying this is a problem (//-style
> comments aren't valid C89 either), just something to keep in mind and
> document.
>
> // Not valid C89
> union
> {
>     float data[2];
>     struct { float x, y; };
> };
>
> /* Valid C89 */
> union foo_union
> {
>     float data[2];
>     struct bar_struct { float x, y; } bar;
> } foo;
>
> Anyone knows if these have been standardized in C99?
>   
Hmm, I did a test with VC7.1, and he's right: on warning level 4, it 
does produce a warning. Even when compiled as C++, it produces a warning.

So this kind of anonymous structure is widely supported but invalid C89 
behavior. I suppose you could pragma around it.