std::locale::id(3cxx)

📦
version 14-20240412 · 16 versions
, in ubuntu noble

🌸 NAME 🌸

okay so welcome to the std::locale::id(3cxx) page, bestie — this one is all about std::locale::id, aka the Facet ID class ✨. No cap, it’s the tiny backstage-pass class that gives locale facets their unique ID energy 💅.

✨ SYNOPSIS ✨

#include <locale>

🎀 Public Member Functions 🎀

  • id () — Constructor. That’s it, that’s the whole vibe.
  • size_t _M_id () const throw () — no description attached in the source, so we’re respecting the mystery 🫶. The exact signature stays exactly as written.

🦋 Friends 🦋

  • template<typename _Facet > const _Facet * __try_use_facet (const locale &) noexcept — friend of the ID class, with its noexcept energy intact.
  • template<typename _Facet > bool has_facet (const locale &) throw () — Test for the presence of a facet.
  • class locale — friend of the ID class.
  • class locale::_Impl — also a friend.
  • template<typename _Facet > const _Facet & use_facet (const locale &) — Return a facet.

💜 Detailed Description 💜

Facet ID class.

The ID class provides facets with an index used to identify them. Every facet class must define a public static member locale::id, or be derived from a facet that provides this member, otherwise the facet cannot be used in a locale. And the locale::id ensures that each class type gets a unique identifier. periodt 💅.

🧚 Constructor & Destructor Documentation 🧚

🌸 std::locale::id::id () [inline] 🌸

Constructor. Short, sweet, iconic.

⭐ template<typename _Facet > bool has_facet (const locale &) [friend] ⭐

Test for the presence of a facet. has_facet tests the locale argument for the presence of the facet type provided as the template parameter. Facets derived from the facet parameter will also return true 💖.

  • Template Parameters
    • _Facet — The facet type to test the presence of.
  • Parameters
    • __loc — The locale to test.
  • Returns
    • true if __loc contains a facet of type _Facet, else false.

💫 template<typename _Facet > const _Facet & use_facet (const locale &) [friend] 💫

Return a facet. use_facet looks for and returns a reference to a facet of type Facet where Facet is the template parameter. If has_facet(locale) is true, there is a suitable facet to return. It throws std::bad_cast if the locale doesn’t contain a facet of type Facet 😭.

  • Template Parameters
    • _Facet — The facet type to access.
  • Parameters
    • __loc — The locale to use.
  • Returns
    • Reference to facet of type Facet.
  • Exceptions
    • std::bad_cast if __loc doesn’t contain a facet of type _Facet.

👑 Author 👑

This page was generated automatically by Doxygen for libstdc++ from the source code. Not me hand-writing it at 3am, but I’m still giving it main character energy 💅.

signed off with love by libstdc++ — that’s the source/version — and the page is std::locale::id(3cxx); the footer doesn’t print a date, so we’re calling it timeless 🫶✨

📦 where this page comes from