std::auto_ptr::auto_ptr(3)

🌸 NAME 🌸

std::auto_ptr::auto_ptr - std::auto_ptr::auto_ptr

Okay bestie, we're looking at the std::auto_ptr::auto_ptr(3) page from the C++ Standard Libary manual. Yes, the title is a whole mouthful — it's giving “constructor with main character energy” — but it's just the constructor page for std::auto_ptr. 💖

✨ Synopsis ✨

Here's the full constructor lineup, exactly as the page serves it:

explicit auto_ptr( X* p = 0 ) throw(); (1) (deprecated in C++11)
                                           (removed in C++17)
auto_ptr( auto_ptr& r ) throw();       (2) (deprecated in C++11)
                                           (removed in C++17)
template< class Y >                    (3) (deprecated in C++11)
auto_ptr( auto_ptr<Y>& r ) throw();        (removed in C++17)
auto_ptr( auto_ptr_ref<X> m ) throw(); (4) (deprecated in C++11)
                                           (removed in C++17)

🚨 Deprecation vibe check: all four are marked deprecated in C++11 and removed in C++17. That's straight from the page, bestie — not me being dramatic.

The big idea: it constructs the auto_ptr from a pointer that refers to the object to manage. Here's the breakdown:

1. Constructs the auto_ptr with pointer p.
2. Constructs the auto_ptr with the pointer held in r. r.release() is called to acquire the ownership of the object.
3. Same as (2). Y* must be implicitly convertible to T*.
4. Constructs the auto_ptr with the pointer held in the auto_ptr instance referred to by m. p.release() is called for the auto_ptr p that m holds to acquire the ownership of the object.

auto_ptr_ref is an implementation-defined type that holds a reference to auto_ptr. std::auto_ptr is implicitly convertible to and assignable from this type. The implementation is allowed to provide the template with a different name or implement equivalent functionality in other ways. 🦋

🎀 Parameters 🎀

• p — a pointer to an object to manage.
• r — another auto_ptr to transfer the ownership of the object from.
• m — an implementation-defined type that holds a reference to auto_ptr.

💅 Notes 💅

Okay so the tea ☕: the constructor and the copy assignment operator from auto_ptr_ref is provided to allow copy-constructing and assigning std::auto_ptr from nameless temporaries. Since its copy constructor and copy assignment operator take the argument as non-const reference, they cannot bind rvalue arguments directly. However, a user-defined conversion can be executed (which releases the original auto_ptr), followed by a call to the constructor or copy-assignment operator that take auto_ptr_ref by value. This is an early implementation of move semantics. 👑

okay that's the whole page, bestie 🫶 — source: http://cppreference.com, version/date: 2024.06.10, page: std::auto_ptr::auto_ptr(3) 💖✨