METAPROGRAMMING(3)

💖 NAME 💖

Type Traits — that's the whole title, bestie ✨

This page lives in the Library Functions Manual section, filed under Type Traits(3), and it's the libstdc++ type-traits catalogue. Everything here is compile time type transformation and information — the page's own words, not mine 🫶 (I mean, it also says that in the Detailed Description section, so like, spoiler alert, whatever 💅).

If you've ever written std::is_integral<T>::value and felt like a genius, congrats, this is your house 🏠✨

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🌸 Classes 🌸

Okay so this is the main event, bestie. Forty-four structs, all in std::, all doing their little type-trait thing. Here they are, in the exact order the page gives them, no cap:

• struct std::__is_member_pointer_helper< _Tp > — is_member_pointer 🙈 (yes it's got the double underscore, it's an implementation-detail icon)
• struct std::add_const< _Tp > — add_const ✨
• struct std::add_cv< _Tp > — add_cv ✨
• struct std::add_lvalue_reference< _Tp > — add_lvalue_reference 💫
• struct std::add_pointer< _Tp > — add_pointer 🎀
• struct std::add_rvalue_reference< _Tp > — add_rvalue_reference 💫
• struct std::add_volatile< _Tp > — add_volatile ✨
• struct std::alignment_of< _Tp > — alignment_of 📐
• struct std::extent< typename, _Uint > — extent 🌈
• struct std::has_virtual_destructor< _Tp > — has_virtual_destructor 💀
• struct std::integral_constant< _Tp, __v > — integral_constant 👑 (genuinely the main character of this whole lineup, ngl)
• struct std::is_abstract< _Tp > — is_abstract 🦋
• struct std::is_arithmetic< _Tp > — is_arithmetic 🔢
• struct std::is_array< typename > — is_array 🍓
• struct std::is_class< _Tp > — is_class 🎀
• struct std::is_compound< _Tp > — is_compound 🧚
• struct std::is_const< typename > — is_const ✨
• struct std::is_empty< _Tp > — is_empty 🫙
• struct std::is_enum< _Tp > — is_enum 🌸
• struct std::is_floating_point< _Tp > — is_floating_point 🎈
• struct std::is_function< typename > — is_function ⭐
• struct std::is_fundamental< _Tp > — is_fundamental 💜
• struct std::is_integral< _Tp > — is_integral 🔢
• struct std::is_lvalue_reference< typename > — is_lvalue_reference 💫
• struct std::is_member_function_pointer< _Tp > — is_member_function_pointer 🙈
• struct std::is_member_object_pointer< _Tp > — is_member_object_pointer 🙈
• struct std::is_object< _Tp > — is_object 🧸
• struct std::is_pointer< _Tp > — is_pointer 🎀
• struct std::is_polymorphic< _Tp > — is_polymorphic 🦋
• struct std::is_reference< _Tp > — is_reference 💫
• struct std::is_rvalue_reference< typename > — is_rvalue_reference 💫
• struct std::is_same< typename, typename > — is_same 👯 (two typenames, one vibe check)
• struct std::is_scalar< _Tp > — is_scalar 🌾
• struct std::is_union< _Tp > — is_union 🤝
• struct std::is_void< _Tp > — is_void 🕳️
• struct std::is_volatile< typename > — is_volatile ⚡
• struct std::rank< typename > — rank 📊
• struct std::remove_all_extents< _Tp > — remove_all_extents 🧹
• struct std::remove_const< _Tp > — remove_const 🧹
• struct std::remove_cv< _Tp > — remove_cv 🧹
• struct std::remove_extent< _Tp > — remove_extent 🧹
• struct std::remove_pointer< _Tp > — remove_pointer 🧹
• struct std::remove_reference< _Tp > — remove_reference 🧹
• struct std::remove_volatile< _Tp > — remove_volatile 🧹

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🎀 Defines 🎀

The macro squad. Copy these exactly, bestie — underscores everywhere, do not freestyle:

• #define _DEFINE_SPEC(_Order, _Trait, _Type, _Value) — the one with actual arguments ✨
• #define _DEFINE_SPEC_0_HELPER — helper numero zero 🌈
• #define _DEFINE_SPEC_1_HELPER — helper numero one 🌈
• #define _DEFINE_SPEC_2_HELPER — helper numero two 🌈

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🦋 Typedefs 🦋

Just two, but they're iconic:

• typedef integral_constant< bool, false > std::false_type — literally false_type 💀
• typedef integral_constant< bool, true > std::true_type — literally true_type 👑

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💜 Variables 💜

• static const _Tp std::integral_constant::value — the value member of integral_constant, static const, _Tp typed. She's the payload 💅

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✨ Detailed Description ✨

Compile time type transformation and information.

That's it. That's the whole detailed description. Short, sweet, and honestly kind of a flex 😭👑

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🔥 Typedef Documentation 🔥

🌸 typedef integral_constant<bool, false> std::false_type 🌸

Okay so this is the false_type typedef — a typedef for false_type, as the page puts it 🫶

Defined at line 78 of file tr1_impl/type_traits 📍

🌸 typedef integral_constant<bool, true> std::true_type 🌸

And this one's the true_type typedef — a typedef for true_type. Yes, the documentation says the thing is the thing. We love a self-aware queen 💅✨

Defined at line 75 of file tr1_impl/type_traits 📍

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🧚 Author 🧚

Generated automatically by Doxygen for libstdc++ from the source code. Not a human, not a group chat, just Doxygen doing its little automated slay 🤖✨

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Okay that's the whole page, bestie — every struct, every define, every typedef, every line number, nothing skipped 🫶

Signing off with the footer energy: this is libstdc++, dated 21 Apr 2009, and the page is Type Traits(3) — catch you in the next manpage 💖🎀🦋