Re: [Boost-users] ADL comment in noncopyable

On Jun 14, 2006, at 3:58 PM, Steven E. Harris wrote:

Peter Dimov writes:

...

One common problem of this kind is

template< class T, class A = std::allocator<T> > class X;

X<int> x;

foo( x ); // searches std

Given that this can be characterized as a problem, what's a "positive" example to illustrate the motivation for this rule? There must be something useful it's meant to enable. Or, rather, I hope there is.

For example the standard might create I/O for pair: template ostream& operator<<(ostream&, pair); Then you might also want to get more specialized behavior for pair (in your own namespace). It would be nice if when pair was given to operator<< both namespace std and namespace MyNamespace were searched for viable overloads. -Howard