std::formatter(3)

✨ NAME ✨

okay so this is std::formatter(3) from the C++ Standard Library, bestie. The name is literally std::formatter — std::formatter. That’s it. No cap. 💅

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🦋 Synopsis 🦋

Defined in header <filesystem>. And yes, this is the (since C++26) era, so mark your calendar. 🗓️

template< class CharT >                          (since C++26)
struct formatter<std::filesystem::path, CharT>;

The template specialization of std::formatter for the std::filesystem::path class lets users convert a pathname to its textual representation using formatting functions. This specialization is debug-enabled — iconic, honestly. ✨

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💅 Member functions 💅

• set_debug_format — enables to format the pathname as an escaped string (public member function)
• parse — parses the format specifier as specified by path-format-spec (public member function)
• format — writes the formatted output as specified by path-format-spec (public member function)

💖 std::formatter<std::filesystem::path>::set_debug_format

constexpr void set_debug_format();

Allows the current object to format pathname as an escaped string. Cute and useful, fr fr. 🎀

🌸 std::formatter<std::filesystem::path>::parse

constexpr auto parse( std::basic_format_parse_context<CharT>& ctx )
    -> std::basic_format_parse_context<CharT>::iterator;

Parses the format specifiers as a path-format-spec and stores the parsed specifiers in the current object.

Returns an iterator past the end of the path-format-spec. Slay. 💅

🦋 std::formatter<std::filesystem::path>::format

template< class FormatContext >

auto format( const std::filesystem::path& p, FormatContext& ctx ) const

    -> FormatContext::iterator;

Let s be p.generic<std::filesystem::path::value_type>() if the g option is used, otherwise p.native(). Writes s into ctx.out() as specified by path-format-spec.

For character transcoding of the pathname:

• The pathname is transcoded from the native encoding for wide character strings to UTF-8 with maximal subparts of ill-formed subsequences substituted with U+FFFD REPLACEMENT CHARACTER if
  • std::is_same_v<CharT, char> is true,
  • std::is_same_v<typename path::value_type, wchar_t> is true, and
  • ordinary literal encoding is UTF-8.
• Otherwise, no transcoding is performed if std::is_same_v<typename path::value_type, CharT> is true.
• Otherwise, transcoding is implementation-defined.

Returns an iterator past the end of the output range. 🫶

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📝 Notes 📝

Feature-test macro __cpp_lib_format_path has value 202403L, std (C++26), and feature: formatting support for std::filesystem::path. periodt. 🔥

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🧚 Example 🧚

This section is incomplete.

Reason: no example. 😭 bestie we gotta add one later, no cap.

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👑 See also 👑

• formatter defines formatting rules for a given type (C++20) (class template).

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🗂️ Category 🗂️

• Todo no example

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Source/version: http://cppreference.com, dated 2024.06.10 — mwah 💋