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

[H. H. <hen...@gm...>]

On Sun, Aug 24, 2008 at 4:53 AM, Henri Häkkinen <hen...@gm...> wrote:

>
>
> On Sun, Aug 24, 2008 at 4:44 AM, Jason McKesson <ko...@gm...> wrote:
>
>>  Henri Häkkinen wrote:
>>
>>
>>
>> On Sun, Aug 24, 2008 at 4:19 AM, Jason McKesson <ko...@gm...>wrote:
>>
>>>  Henri Häkkinen wrote:
>>>
>>> Does anyone have anything to say on this, please? I am currently working
>>> hard on the GLM and I think we should resolve the issue of how we actually
>>> define the math types.
>>>
>>>  Well, the VC++ compiler issue pretty much ends #2 as a possibility. If
>>> #1 doesn't work for you, that leaves #3.
>>>
>>
>> Well no, this is not true at all. The VC compiler issues is only about
>> anonymous structures. For example, this generates a warning:
>>
>> typedef struct GLMvec2f_s {
>>   union {
>>     GLfloat v[2];
>>     struct {
>>       GLfloat x, y;
>>     }
>>   };
>> } GLMvec2f;
>>
>> While this does not:
>>
>> typedef struct GLMvec2f_s {
>>   union {
>>     GLfloat v[2];
>>     struct GLMvec2fcoords_s {
>>       GLfloat x, y;
>>     }
>>   };
>> } GLMvec2f;
>>
>>   Admittedly it's been a while since I last used pure C, but if I'm
>> reading that right, to access the x or y members, I would need:
>>
>> GLMvec2f someValue;
>>
>> someValue.GLMvec3fcoords_s.x = 0.5f
>>
>> This is a pretty clear violation of design goal #2: Simplicity. And if the
>> inner struct can't be accessed with a simple ".x", then what's the point in
>> having it at all?
>>
>
> No that is not correct at all.
>
> There is a difference between the name of the structure and the name of the
> variable. When you write in C like this:
>
> struct FOO {
>   int baz;
> } fizban;
>
> You access baz inside the struct like this:
>
> fizban.baz = 12;
>
> When we have the vector type:
>
> typedef struct GLMvec2f_s {
>   union {
>     GLfloat v[2];
>     struct GLMvec2fcoords_s {
>       GLfloat x, y;
>     };
>   };
> } GLMvec2f;
>
> You access it normally;
>
> GLMvec2f v;
> v.x = 10.0f;
>
> The 'GLMvec2fcoords_s' is a structure name, nor a variable name.
>

TYPO: s/nor/not/


>
>
>
>>
>> -------------------------------------------------------------------------
>> This SF.Net email is sponsored by the Moblin Your Move Developer's
>> challenge
>> Build the coolest Linux based applications with Moblin SDK & win great
>> prizes
>> Grand prize is a trip for two to an Open Source event anywhere in the
>> world
>> http://moblin-contest.org/redirect.php?banner_id=100&url=/
>> _______________________________________________
>> Glsdk-devel mailing list
>> Gls...@li...
>> https://lists.sourceforge.net/lists/listinfo/glsdk-devel
>>
>>
>
>
> --
> Henri 'henux' Häkkinen
>
>


-- 
Henri 'henux' Häkkinen