basic_format_arg() noexcept;
template<class T> explicit basic_format_arg(T& v) noexcept;
explicit operator bool() const noexcept;
template<class T> explicit handle(T& val) noexcept;
void format(basic_format_parse_context<char_type>& parse_ctx, Context& format_ctx) const;
template<class Visitor, class Context>
decltype(auto) visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
template<class Context = format_context, class... Args>
format-arg-store<Context, Args...> make_format_args(Args&&... fmt_args);
template<class... Args>
format-arg-store<wformat_context, Args...> make_wformat_args(Args&&... args);
basic_format_args() noexcept;
template<class... Args>
basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
basic_format_arg<Context> get(size_t i) const noexcept;