c++ - How to replace std::is_same_v with std::is_same

Question

I have this code containing std::is_same_v available with C++17. But I've stuck with C++14 due to toolchain limitation.

template<class T, class O = T>
using IteratorOnly = std::enable_if_t<
    !std::is_same_v<typename std::iterator_traits<T>::value_type, void>, O
>;

How can I replace std::is_same_v with std::is_same? Is there any workaround to be able to compile the code with just C++14?

Answer 1

The error got resolved by @Someprogrammerdude comment about a is_same_v helper variable template defined here. My final code is

#ifdef My_OLD_TOOL_CHAIN

template< class T, class U >
inline constexpr bool is_same_v = std::is_same<T, U>::value;

template<class T, class O = T>
using IteratorOnly = std::enable_if_t<
    !is_same_v<typename std::iterator_traits<T>::value_type, void>, O
>;

#else // My_OLD_TOOL_CHAIN

template<class T, class O = T>
using IteratorOnly = std::enable_if_t<
    !std::is_same_v<typename std::iterator_traits<T>::value_type, void>, O
>;

#endif // My_OLD_TOOL_CHAIN