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Difference between revisions of "cpp/memory/enable shared from this/weak from this"

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{{cpp/memory/enable_shared_from_this/title | weak_from_this}}
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{{cpp/memory/enable_shared_from_this/title|weak_from_this}}
 
{{cpp/memory/enable_shared_from_this/navbar}}
 
{{cpp/memory/enable_shared_from_this/navbar}}
 
{{dcl begin}}
 
{{dcl begin}}
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{{dcl | since=c++17| num=1 | 1=
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{{dcl|num=1|since=c++17|
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std::weak_ptr<T> weak_from_this();
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std::weak_ptr<T> weak_from_this() noexcept;
 
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}}
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{{dcl|num=2|since=c++17|
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std::weak_ptr<T const> weak_from_this() const;
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std::weak_ptr<T const> weak_from_this() const noexcept;
 
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Returns a {{c|std::weak_ptr<T>}} that tracks ownership of {{c|*this}} by all existing {{c|std::shared_ptr}} that refer to {{c|*this}}.
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Returns a {{c/core|std::weak_ptr<T>}} that tracks ownership of {{c|*this}} by all existing {{lc|std::shared_ptr}} that refer to {{c|*this}}.
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===Notes===
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This is a copy of the the private mutable {{tt|weak_ptr}} member that is part of    {{tt|enabled_shared_from_this}}.  
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===Return value===
 
===Return value===
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{{c|std::weak_ptr<T>}} that shares ownership of {{c|*this}} with pre-existing {{c|std::shared_ptr}}s
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{{box|{{rlpsi|/#weak_this}}}}
  
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===Exceptions===
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===Notes===
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@2@ {{noexcept}}
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{{feature test macro|__cpp_lib_enable_shared_from_this|std=C++17|value=201603L|{{tt|std::enable_shared_from_this::weak_from_this}}}}
  
 
===Example===
 
===Example===
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Latest revision as of 00:50, 22 October 2024

 
C++
 
Utilities library
General utilities
Relational operators (deprecated in C++20)
 
Dynamic memory management
Uninitialized memory algorithms
Constrained uninitialized memory algorithms
Allocators
Garbage collection support
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)
(C++11)(until C++23)



 
std::enable_shared_from_this
 
std::weak_ptr<T> weak_from_this() noexcept;
 (1) (since C++17)
std::weak_ptr<T const> weak_from_this() const noexcept;
 (2) (since C++17)

Returns a std::weak_ptr<T> that tracks ownership of *this by all existing std::shared_ptr that refer to *this.

Contents

[edit] Return value

weak_this

[edit] Notes

Feature-test macro Value Std Feature
__cpp_lib_enable_shared_from_this 201603L (C++17) std::enable_shared_from_this::weak_from_this

[edit] Example

This section is incomplete
Reason: no example

[edit] See also

(C++11)
 smart pointer with shared object ownership semantics
(class template) [edit]
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