std::formattable
<format>
concept formattable = /* formattable_with */<
std::remove_reference_t <T>,
std::basic_format_context </* fmt_iter_for */<CharT>, CharT>
using /* fmt_iter_for */ = /* unspecified */;
class Formatter =
typename Context::template
formatter_type<std::remove_const_t <T>> >
concept /* formattable_with */ =
std::semiregular <Formatter> &&
requires (Formatter& f, const Formatter& cf, T&& t, Context fc,
std::basic_format_parse_context <
typename Context::char_type
> pc) {
{ f.parse(pc) } -> std::same_as <typename decltype(pc)::iterator>;
{ cf.format(t, fc) } -> std::same_as <typename Context::iterator>;
The concept formattable specifies that std::formatter <std::remove_cvref_t <T>, CharT> meets the requirements of BasicFormatter and Formatter (if std::remove_reference_t <T> is const-qualified).
The exposition-only alias template /* fmt_iter_for */ yields an unspecified type that satisfies std::output_iterator <const CharT&>.
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 3925 | C++23 | the second template argument of std::basic_format_context was not provided | provided |
[edit] See also
(named requirement)