Re: Null Pointer Considerations
James Hopkin wrote:
Seungbeom Kim wrote:
James Hopkin wrote:
template <class C> struct S {};
template <class C> struct S<C*> {};
template <class C> void f(C)
{
S<C> s;
}
void test() { f(nullptr); }
What would C be in S<C*> here?
Er, I don't know, now you mention it. Looks like my thought
process didn't go that far. The example came to mind when I
read this in the proposal:
"nullptr_t matches both a T* and a T::* partial specialization."
So what, indeed, is T in those cases?
Implementation defined. Presumably an otherwise unnamable type,
with unspecified properties (and possibly incomplete?), but the
paper should definitly be amended to say this. And to consider
such things as:
template< typename T >
void
f( T* p ) // when instantiated with nullptr...
{
T obj ; // Illegal, T is incomplete.
T const* pc ; // Why not?
int T::* pm ; // ??? (I'd say illegal, T isn't a
// class type.)
}
template< typename T >
void
g( int T::* p ) // when instantiated with nullptr...
{
T obj ; // Illegal, T is incomplete.
T const* pc ; // Why not?
}
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