Re: [MiNT] XaAES modifications and clarification

[Kåre Andersen <kareandersen@gmail.com>]

2009/12/10 Vincent Rivière <vincent.riviere@freesbee.fr>:
> Kåre Andersen a écrit :
>>>
>>> struct remember_alloc; // ???
>>> struct remember_alloc
>>> {
>>>       struct remember_alloc *next;
>>>       void *addr;
>>> };
>>>
>>> what is happening here, why the double declaration (see: ???)
>>
>> Not a double declaration; The "empty" statement is a declaration, the
>> second is a definition. A declaration (or "forward declaration") lets
>> the compiler know that there is code for a symbol like this somewhere
>> (same source file or other linked in file). Often you find them at the
>> top of the source while the definition follows in the code "body"
>> somewhere - and has the actual function.
>
> This is the basic pattern for a linked list.
> It uses a recursive structure.
>
> The compiler consider a structure as defined after the closing brace. So
> without a special artifice, a structure member can't refer to itself,
> because the type has not been defined yet.
>
> A forward declaration is not enough to declare a variable using the type of
> the struct, but it is enough to declare a pointer to it.
> So this does the trick.


Thanks Vincent, I missed that :)

/Kåre