__GNU_CXX::HASH_MAP(3)

💖 __gnu_cxx::hash_map< _Key, _Tp, _HashFn, _EqualKey, _Alloc > 💖

okay bestie, come sit with me, we're reading a libstdc++ manpage and honestly? it's giving deep lore. this one lives in the Library Functions Manual, it's an __gnu_cxx thing, and yes the title up top got truncated to __gnu_cxx:..., _Alloc >(3) because even the typesetter gave up. we move. 🫶

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✨ NAME ✨

__gnu_cxx::hash_map< _Key, _Tp, _HashFn, _EqualKey, _Alloc > — that's the whole name, no notes, she's a template and she knows it 💅

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🌸 SYNOPSIS 🌸

#include <hash_map>

🎀 Public Types 🎀

okay so these are all just typedefs that forward straight to the underlying _Ht (except two of them, watch me):

• typedef _Ht::allocator_type allocator_type
• typedef _Ht::const_iterator const_iterator
• typedef _Ht::const_pointer const_pointer
• typedef _Ht::const_reference const_reference
• typedef _Tp data_type — yep, this one's literally just _Tp, iconic
• typedef _Ht::difference_type difference_type
• typedef _Ht::hasher hasher
• typedef _Ht::iterator iterator
• typedef _Ht::key_equal key_equal
• typedef _Ht::key_type key_type
• typedef _Tp mapped_type — also just _Tp, she's matching with data_type, cute
• typedef _Ht::pointer pointer
• typedef _Ht::reference reference
• typedef _Ht::size_type size_type
• typedef _Ht::value_type value_type

🌈 Public Member Functions 🌈

constructors first, because entrance, obviously:

• template<class _InputIterator> hash_map (_InputIterator __f, _InputIterator __l)
• template<class _InputIterator> hash_map (_InputIterator __f, _InputIterator __l, size_type __n)
• template<class _InputIterator> hash_map (_InputIterator __f, _InputIterator __l, size_type __n, const hasher &__hf)
• template<class _InputIterator> hash_map (_InputIterator __f, _InputIterator __l, size_type __n, const hasher &__hf, const key_equal &__eql, const allocator_type &__a=allocator_type())
• hash_map (size_type __n)
• hash_map (size_type __n, const hasher &__hf)
• hash_map (size_type __n, const hasher &__hf, const key_equal &__eql, const allocator_type &__a=allocator_type())

and now the whole roster, alphabetized like a good little API:

• iterator begin ()
• const_iterator begin () const
• size_type bucket_count () const
• void clear ()
• size_type count (const key_type &__key) const
• size_type elems_in_bucket (size_type __n) const
• bool empty () const
• iterator end ()
• const_iterator end () const
• pair< iterator, iterator > equal_range (const key_type &__key)
• pair< const_iterator, const_iterator > equal_range (const key_type &__key) const
• size_type erase (const key_type &__key)
• void erase (iterator __f, iterator __l)
• void erase (iterator __it)
• iterator find (const key_type &__key)
• const_iterator find (const key_type &__key) const
• allocator_type get_allocator () const
• hasher hash_funct () const
• template<class _InputIterator> void insert (_InputIterator __f, _InputIterator __l)
• pair< iterator, bool > insert (const value_type &__obj)
• pair< iterator, bool > insert_noresize (const value_type &__obj)
• key_equal key_eq () const
• size_type max_bucket_count () const
• size_type max_size () const
• _Tp & operator[] (const key_type &__key)
• void resize (size_type __hint)
• size_type size () const
• void swap (hash_map &__hs)

🦋 Friends 🦋

one (1) bestie, and it's the equality operator:

• template<class _K1, class _T1, class _HF, class _EqK, class _Al> bool operator== (const hash_map< _K1, _T1, _HF, _EqK, _Al > &, const hash_map< _K1, _T1, _HF, _EqK, _Al > &)

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👑 Detailed Description 👑

here's the actual declaration, in all her main-character glory:

template<class _Key, class _Tp, class _HashFn = hash<_Key>, class _EqualKey
    = equal_to<_Key>, class _Alloc = allocator<_Tp>>
class __gnu_cxx::hash_map< _Key, _Tp, _HashFn, _EqualKey, _Alloc >

This is an SGI extension.

Todo: Needs documentation! See http://gcc.gnu.org/onlinedocs/libstdc++/manual/documentation_style.html

like... the todo literally says it needs documentation 😭 not me reading a manpage that admits it's undocumented. we love transparency tho. 🫶

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🧚 Author 🧚

Generated automatically by Doxygen for libstdc++ from the source code.

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and that's the whole vibe check, bestie 💜 this page came from libstdc++, dated the manpage footer way, and yes — Doxygen wrote it, not a human, so if you see a typo, that's between you and the source code. slay, go hash something, periodt. 🎀✨