"Richard Guenther" <[EMAIL PROTECTED]> writes:
> > > On Jan 17, 2008 2:12 PM, Dragan Milenkovic <[EMAIL PROTECTED]> wrote:
> > > > Richard Guenther wrote:
> > > > [snip]
> > > > >> template <typename T>
> > > > >> struct Foo
> > > > >> {
> > > > >> template <typename Z>
> > > > >> friend void func(const Foo &);
> > > > >> };
> > > > >>
> > > > >> void check(const Foo<int> & x)
> > > > >> {
> > > > >> // Foo<int> weird; // uncomment this line and all works
> > > > >>
> > > > >> func<int>(x); // <-- ERROR
> > > > >> }
> > > > >>
> > > > >>
> > > > >> Tested with gcc 4.0 - 4.3, and all behave the same:
> > > > >>
> > > > >> "error: 'func' was not declared in this scope"
> > > > >>
> > > > >> but it works if you uncomment the weird line.
> > > > >
> > > > > Actually even with the weird line the program is invalid. What are
> > > > > you trying to do? ;)
> > > > >
> > > > > Richard.
> > > >
> > > > Ok... afaik, that func should be defined on that very place where it is
> > > > declared as friend. But could you please elaborate why it is invalid,
> > > > since you made me start questioning my C++ knowledge... :-D
> > >
> > > How should name-lookup find func?
> >
> > It should use argument dependent lookup. This is like the common case
> > of
> >
> > class x
> > {
> > friend x operator+(const& x, const& x) { return x.var + x.var; }
> > };
> >
> > in which x::operator+ is found without taking special action.
>
> Well, first I think you'd need friend-injection or otherwise a global
> decl of the function.
ADL works without friend injection. Look at 3.4.2
[basic.lookup.koenig] in C++98.
> Second I thought argument dependent
> name-lookup only applies to namespaces, not classes.
No.
> EDG rejects this consistently btw.
Well, I'm probably misinterpreting the example. Adding the templates
must change it somehow.
For example, this works fine, even without -ffriend-injection:
class x { friend x operator+(const x& x1, const x& x2); };
x foo(x x1, x x2) { return x1 + x2; }
Ian
