std::weak_ptr::operator=(3)

Hey bestie! Welcome to the std::weak_ptr::operator=(3) page from the C++ Standard Libary manual 💖✨ (yes, “Libary” is exactly how the manual name is spelled up there — we respect the typo, no cap).

💖 NAME 💖

std::weak_ptr::operator= — std::weak_ptr::operator=. That’s it, that’s the name. She’s self-titled and honestly? Main character energy 👑.

🌸 Synopsis 🌸

Okay so there are five overloads, all chillin’ since C++11 and all noexcept. Here’s the exact lineup, bestie:

weak_ptr& operator=( const weak_ptr& r ) noexcept;      (1) (since C++11)
template< class Y >                                     (2) (since C++11)
weak_ptr& operator=( const weak_ptr<Y>& r ) noexcept;
template< class Y >                                     (3) (since C++11)
weak_ptr& operator=( const shared_ptr<Y>& r ) noexcept;
weak_ptr& operator=( weak_ptr&& r ) noexcept;           (4) (since C++11)
template< class Y >                                     (5) (since C++11)
weak_ptr& operator=( weak_ptr<Y>&& r ) noexcept;

The vibe of the whole thing: replaces the managed object with the one managed by r. The object is shared with r. If r manages no object, *this manages no object too. Periodt. 💅

Specifically:

• Overloads 1-3) — equivalent to std::weak_ptr<T>(r).swap(*this).
• Overloads 4,5) — equivalent to std::weak_ptr<T>(std::move(r)).swap(*this).

🎀 Parameters 🎀

• r — smart pointer to share an object with 💖

🫶 Return value 🫶

*this. That’s the whole return value. She gives herself back. Iconic.

📝 Notes 📝

Implementation tea ☕: the implementation may meet the requirements without creating a temporary weak_ptr object. No extra temp needed, lowkey efficient.

💀 Defect reports 💀

The following behavior-changing defect reports were applied retroactively to previously published C++ standards. Yes bestie, retroactive glow-ups are real.

• DR LWG 2315 — applied to C++11. Behavior as published: move semantic was not enabled for weak_ptr. Correct behavior: enabled.

👀 See also 👀

• constructor — creates a new weak_ptr (public member function) ✨
• swap — swaps the managed objects (public member function) 🔄

That’s the whole page, bestie 🫶 — brought to you by http://cppreference.com, dated 2024.06.10, and filed under std::weak_ptr::operator=(3). Go forth and assign responsibly 💖✨