c++14

There's an example on cppreference about the using alias. This example fails because int has no member foo : template<typename...> using void_t = void; template<typename T> void_t<typename T::foo> f(); f<int>(); // error, int does not have a nested type foo This is clear, but when I tried putting the void_t part in the parameter list it unexpectedly compiled: template<typename...> using void_t = void; template<typename T> void f(void_t<typename T::foo>); f<int>(); It compiles on clang but not in gcc. Is this a bug? template<class...>struct voider{using type=void;}; template<class...Ts>using

After answering this question and reading this talk and looking at this code , I want to implement constexpr find with just simple array class. Consider following example: #include <cstddef> template <class It, class T> constexpr auto constexpr_find(const It& b, const It& e, T value) { auto begin = b; while (begin != e) { if (*begin == value) break; ++begin; } return *begin; } template<typename T, size_t N> class array { public: typedef T* iterator; typedef const T* const_iterator; constexpr auto begin() const { return const_iterator(array_); } constexpr auto end() const { return const

Is it permitted to declare a non-const reference as constexpr ? Example code: int x = 1; constexpr int& r = x; This is accepted by gcc and clang (I tried several current and past versions of both, back to C++11, and all accepted it). However I think it should not be accepted because C++14 [dcl.constexpr/9] says: if a constexpr specifier is used in a reference declaration, every full- expression that appears in its initializer shall be a constant expression and x is not a constant expression. The language in the latest C++17 draft of [dcl.constexpr] changed and doesn't even mention constexpr

I had nested partially specialized template code working with VS 2015 until I discovered that it was not standards-compliant . I want it to be so I twisted my code to overcome the former issue and also that one and have now hit a hard wall. Using variadic templates and partial specialization I would like to fill an array at compile-time given a fixed set of parameters. What I want to achieve also seems similar to this answer but I did not manage to make it work. Consider the following program: #include <cstdlib> template <typename T, std::size_t Size> struct Array; template <typename T, std:

An answer to C++14 Variable Templates: what is the purpose? Any usage example? proposes a usage example of variable templates + generic lambdas that would look something like this: void some_func() { template<typename T> std::map<int, T> storage; auto store = []<typename T>(int key, const T& value) { storage<T>.insert(key, value) }; store(0, 2); store(1, "Hello"s); store(2, 0.7); // All three values are stored in a different map, according to their type. } Unfortunately it doesn't compile so I've tried to "fix" it and this is my attempt so far. #include <map> template<typename T> std::map<int,