Le 22/04/13 16:24, Krzysztof Czainski a écrit :
2013/4/22 Vicente J. Botet Escriba <vicente.botet@wanadoo.fr>
Out of curiosity, can you detect the difference? What can you do with
constexpr values that you can't with static const ones?
Even if most of the uses of integral_constant is to use its member ::value integral constant defines also the operator(), so it is a nullary functor.
integral_constant<int, 1> a; constexpr int f();
template <int I> void g();
template <typename F> void h(F&& fct) { g<fct()>(); } h(&f); h(a);
The last sentence will not compile if the operator() is not a constexpr and it can not be a constexpr if ::value is not a consexpr, or can it?
Really?? I thought a static constant can be used in constexpr functions, just like in C++03 it could be used as a non-type template parameter or static array size. Am I wrong here?
You are right, but I was not using an static constant but a static function. Best, Vicente