In the source code, it describes that gcc 4.8 doesn’t support std::to_string . And you guys implemented it.
namespace detail {
class DummyClassForToString final {};
} // namespace detail
} // namespace guts
} // namespace c10
namespace std {
// We use SFINAE to detect if std::to_string exists for a type, but that only
// works if the function name is defined. So let's define a std::to_string for a
// dummy type. If you're getting an error here saying that this overload doesn't
// match your std::to_string() call, then you're calling std::to_string() but
// should be calling c10::guts::to_string().
inline std::string to_string(c10::guts::detail::DummyClassForToString) {
return "";
}
} // namespace std
namespace c10 {
namespace guts {
namespace detail {
template <class T, class Enable = void>
struct to_string_ final {
static std::string call(T value) {
std::ostringstream str;
str << value;
return str.str();
}
};
// If a std::to_string exists, use that instead
template <class T>
struct to_string_<T, void_t<decltype(std::to_string(std::declval<T>()))>>
final {
static std::string call(T value) {
return std::to_string(value);
}
};
} // namespace detail
template <class T>
inline std::string to_string(T value) {
return detail::to_string_<T>::call(value);
}
You guys implemented the C++17 feature void_t but parameter packs was introduced in C++11.
So is there a problem?