std::unorde...emplace_hint(3)

💅 NAME

std::unordered_multiset::emplace_hint — bestie, it's literally std::unordered_multiset::emplace_hint, the C++ standard library icon that it is 🎀 (manual name: C++ Standard Libary, no that's not a typo of mine, that's just how the page spells it, iykyk)

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✨ Synopsis

Okay so here's the whole vibe — this is a template, and it's been around (since C++11):

template< class... Args >
iterator emplace_hint( const_iterator hint, Args&&... args );

So what does it do? It inserts a new element into the container, and it uses hint as a suggestion as to where the element should go. A suggestion, bestie — not a demand 🫶

The constructors of the key and mapped value get called with exactly the same arguments as supplied to the function, forwarded with std::forward<Args>(args).... No extra seasoning, no substitutions ✨

And now the part that actually matters, so pay attention 🔥:

• If, after the operation, the new number of elements is greater than old max_load_factor() * bucket_count(), a rehashing takes place.
• If rehashing occurs (because of the insertion), all iterators are invalidated 💀
• Otherwise (no rehashing), iterators are not invalidated. Slay.

No cap, that iterator invalidation clause is the main character here. Read it twice.

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🌸 Parameters

• hint — an iterator, used as a suggestion as to where to insert the new element. It's giving "polite recommendation," not "binding contract" 💖
• args — the arguments to forward to the constructor of the element 🧚

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⭐ Return value

An iterator to the inserted element. That's it, that's the return value 👑

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🦋 Exceptions

If an exception is thrown for any reason, this function has no effect — that's the strong exception safety guarantee, and honestly? Obsessed. She's safe, she's strong, she's not leaving you with half-inserted chaos 😭💜

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🌈 Complexity

Amortized constant on average. Worst case linear in the size of the container. So like, usually a vibe check passes instantly, but sometimes she has to look at literally everything 🙈

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🍓 Example

This section is incomplete.

Reason: no example

Not me showing up to the group chat with a Reason: no example 😭 the docs said "figure it out bestie" 💀

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👑 See also

• emplace — constructs element in-place (public member function)
• insert — inserts elements or nodes (since C++17) (public member function)

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🎀 Category:

• Todo no example

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Okay bestie, that's the whole page, hope you ate it up 🫶✨ — this was pulled from http://cppreference.com, dated 2024.06.10, and the page header/footer around it all reads std::unorde...emplace_hint(3) because someone at cppreference let the column width win 💅 mwah, go insert something 💖