Boost C++ Libraries

template<class Expected, template<class...> class Op, class... Args>
using is_detected_exact = is_same<Expected, detected_t<Op, Args...> >;

template<class Expected, template<class...> class Op, class... Args>
constexpr bool is_detected_exact_v = is_detected_exact<Op, Args...>::value;

C++ Standard Paper: N4502

Compiler Compatibility: Requires C++11 variadic templates and C++11 template aliases.

Header: #include <boost/type_traits/is_detected_exact.hpp>

The type is_detected_exact<To, Op, Args> is an alias for true_type if the result of Op<Args> is type To. Otherwise it's the type false_type;

Examples:

template<class T>
using difference_t = typename T::difference_type;

static_assert(boost::is_detected_exact_v<std::ptrdiff_t, difference_t, T>);

See also: is_detected, is_detected_convertible.