20 General utilities library [utilities]

20.20 Formatting [format]

20.20.6 Arguments [format.arguments]

20.20.6.3 Class template basic_­format_­args [format.args]

namespace std { template<class Context> class basic_format_args { size_t size_; // exposition only const basic_format_arg<Context>* data_; // exposition only public: 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; }; }
An instance of basic_­format_­args provides access to formatting arguments.
Implementations should optimize the representation of basic_­format_­args for a small number of formatting arguments.
[Note 1:
For example, by storing indices of type alternatives separately from values and packing the former.
— end note]
basic_format_args() noexcept;
Effects: Initializes size_­ with 0.
template<class... Args> basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
Effects: Initializes size_­ with sizeof...(Args) and data_­ with store.args.data().
basic_format_arg<Context> get(size_t i) const noexcept;
Returns: i < size_­ ? data_­[i] : basic_­format_­arg<Context>().