3 variant questions

[Saaa]

"Daniel Keep" <daniel.keep.lists at gmail.com> wrote in message 
news:gubip2$187c$1 at digitalmars.com...
>
>
> Saaa wrote:
>> I just noticed D1 does have std.stdarg.
>> I shouldn't just search on the website :(
>> (where it is missing on the phobos page)
>>
>>> import std.stdarg;
>>>
>>> assert( _arguments[0] is typeid(int*) );
>>> auto arg = va_arg!(int*)(_argptr);
>>> *arg = 10;
>>>
>>> Probably.
>> :D
>>>  -- Daniel
>>
>> So, you make arg point to the same as va_arg.
>
> No, va_arg is a function.
I meant to write _argptr :)

>
>> Why is this extra step necessary and why won't simple casting not work?
>
> You should never directly work with _argptr.  It's not guaranteed to be
> a simple pointer.  For example, I believe that GCC will sometimes use
> registers (God only knows WHY).
ok...
>
> var_arg!(T) will convert _argptr into the type you specify and it will
> also advance _argptr to the next argument.
What would happen if you'd cast it incorrectly if it wasn't a simple pointer 
? :D

>
>  -- Daniel