Re: [MiNT] XaAES modifications and clarification

[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.

--
Vincent Rivière