std::unorde...bucket_count(3)

🎀 NAME 🎀

std::unordered_multimap::max_bucket_count — std::unordered_multimap::max_bucket_count (the name is literally the same twice, and honestly? iconic 💅)

okay so bestie, you’re on the std::unorde...bucket_count(3) page from the C++ Standard Libary — yes that’s the manual name, and we’re about to make max bucket count make sense ✨

✨ Synopsis ✨

size_type max_bucket_count() const;  (since C++11)

Since C++11, this member function is right there giving you the maximum number of buckets the container can hold because of system or library implementation limitations. It’s not “infinite buckets era,” it’s “system/library says this is the cap” era 😭.

🧸 Parameters 🧸

(none) — literally no parameters. She takes nothing, she returns the max, she leaves 💀

🌸 Return value 🌸

Maximum number of buckets. That’s the whole return value, no extra lore 👑

⚡ Complexity ⚡

Constant. That’s it — constant complexity, no extra lore 🔥

🍓 Example 🍓

// Run this code

#include <iostream>
#include <unordered_map>

int main()
{
    struct Ha { std::size_t operator()(long x) const { return
       std::hash<long>{}(x); }; };

    auto c1 = std::unordered_multimap<char, long>{};
    auto c2 = std::unordered_multimap<long, long>{};
    auto c3 = std::unordered_multimap<long, long, std::hash<int>>{};
    auto c4 = std::unordered_multimap<long, long, Ha>{};

    std::cout
        << "Max bucket count of\n" << std::hex << std::showbase
        << "c1: " << c1.max_bucket_count() << '\n'
        << "c2: " << c2.max_bucket_count() << '\n'
        << "c3: " << c3.max_bucket_count() << '\n'
        << "c4: " << c4.max_bucket_count() << '\n'
        ;
}

Possible output:

Max bucket count of
c1: 0xfffffffffffffff
c2: 0xfffffffffffffff
c3: 0xfffffffffffffff
c4: 0xaaaaaaaaaaaaaaa

🦋 See also 🦋

• bucket_count — returns the number of buckets (public member function) 💖

source/version: cppreference.com ✨ date: 2024.06.10 🫶 manual tag: std::unorde...bucket_count(3) 💜