type_traits.h

 
#include <type_traits>
 
#if __cplusplus < 201703L
 
#ifndef CTRL_UTILS_TYPE_TRAITS_H_
#define CTRL_UTILS_TYPE_TRAITS_H_
 
namespace std {
 
template<class...> struct conjunction : std::true_type { };
template<class B1> struct conjunction<B1> : B1 { };
template<class B1, class... Bn>
struct conjunction<B1, Bn...> 
    : std::conditional_t<bool(B1::value), conjunction<Bn...>, B1> {};
 
template<class... B>
constexpr bool conjunction_v = conjunction<B...>::value;
 
template<class B1, class B2>
constexpr bool is_convertible_v = is_convertible<B1, B2>::value;
 
}  // namespace std
 
#endif  // CTRL_UTILS_TYPE_TRAITS_H_
 
#endif  // __cplusplus