std::experimental::weak_ptr<T>::weak_ptr

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Experimental

Technical Specification

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Extensions for concurrency 2 (concurrency TS v2)

Concepts (concepts TS)

Ranges (ranges TS)

Reflection (reflection TS)

Mathematical special functions (special functions TR)

Experimental Non-TS

Pattern Matching

Linear Algebra

std::execution

Contracts

2D Graphics

 

Library fundamentals

experimental::optional

experimental::any

experimental::basic_string_view

experimental::sample

experimental::shared_ptr

experimental::weak_ptr

experimental::apply

experimental::invocation_typeexperimental::raw_invocation_type

experimental::search

experimental::default_searcherexperimental::make_default_searcher

experimental::boyer_moore_searcherexperimental::make_boyer_moore_searcher

experimental::boyer_moore_horspool_searcherexperimental::make_boyer_moore_horspool_searcher

Type-erased and polymorphic allocators

Variable templates for type traits

 

std::experimental::weak_ptr

weak_ptr::weak_ptr

Members and non-members identical to those of std::weak_ptr

 

constexpr weak_ptr() noexcept;	(1)	(library fundamentals TS)
weak_ptr( const weak_ptr& r ) noexcept;	(2)	(library fundamentals TS)
template< class Y > weak_ptr( const weak_ptr<Y>& r ) noexcept;	(2)	(library fundamentals TS)
template< class Y > weak_ptr( const std::experimental::shared_ptr<Y>& r ) noexcept;	(2)	(library fundamentals TS)
weak_ptr( weak_ptr&& r ) noexcept;	(3)	(library fundamentals TS)
template< class Y > weak_ptr( weak_ptr<Y>&& r ) noexcept;	(3)	(library fundamentals TS)

Constructs a new weak_ptr that potentially shares an object with r.

1) Default constructor. Constructs empty weak_ptr.

2) Constructs new weak_ptr which shares an object managed by r. If r manages no object, *this manages no object too. The templated overloads don't participate in overload resolution unless either Y* is implicitly convertible to T*, or Y is the type "array of N U" for some type U and some number N, and T is the type "array of unknown bound of (possibly cv-qualified) U".

3) Move constructors. Moves a weak_ptr instance from r into *this. After this, r is empty and r.use_count() == 0. The templated overload doesn't participate in overload resolution unless either Y* is implicitly convertible to T*, or Y is the type "array of N U" for some type U and some number N, and T is the type "array of unknown bound of (possibly cv-qualified) U".

Parameters

r

-

a std::experimental::shared_ptr or std::experimental::weak_ptr that will be viewed by this std::experimental::weak_ptr

Exceptions

noexcept specification:  

noexcept

  

Example

See also

(constructor)	creates a new weak_ptr (public member function of std::weak_ptr<T>)
operator=	assigns the weak_ptr (public member function of std::weak_ptr<T>)

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