std::weak_ptr< _Tp > Class Template Reference

Inherits std::__weak_ptr< _Tp, _Lp >.

Public Types
using	element_type = typename remove_extent< _Tp >::type

Public Member Functions
template<typename _Yp , typename = _Constructible<const shared_ptr<_Yp>&>>
	weak_ptr (const shared_ptr< _Yp > &__r) noexcept
	weak_ptr (const weak_ptr &) noexcept=default
template<typename _Yp , typename = _Constructible<const weak_ptr<_Yp>&>>
	weak_ptr (const weak_ptr< _Yp > &__r) noexcept
	weak_ptr (weak_ptr &&) noexcept=default
template<typename _Yp , typename = _Constructible<weak_ptr<_Yp>>>
	weak_ptr (weak_ptr< _Yp > &&__r) noexcept
bool	expired () const noexcept
shared_ptr< _Tp >	lock () const noexcept
template<typename _Yp >
_Assignable< const shared_ptr< _Yp > & >	operator= (const shared_ptr< _Yp > &__r) noexcept
weak_ptr &	operator= (const weak_ptr &__r) noexcept=default
template<typename _Yp >
_Assignable< const weak_ptr< _Yp > & >	operator= (const weak_ptr< _Yp > &__r) noexcept
weak_ptr &	operator= (weak_ptr &&__r) noexcept=default
template<typename _Yp >
_Assignable< weak_ptr< _Yp > >	operator= (weak_ptr< _Yp > &&__r) noexcept
template<typename _Tp1 >
bool	owner_before (const __shared_ptr< _Tp1, _Lp > &__rhs) const noexcept
template<typename _Tp1 >
bool	owner_before (const __weak_ptr< _Tp1, _Lp > &__rhs) const noexcept
void	reset () noexcept
void	swap (__weak_ptr &__s) noexcept
long	use_count () const noexcept

Related Functions
(Note that these are not member functions.)
template<typename _Tp >
void	swap (weak_ptr< _Tp > &__a, weak_ptr< _Tp > &__b) noexcept

Detailed Description

template<typename _Tp>
class std::weak_ptr< _Tp >

A non-owning observer for a pointer owned by a shared_ptr.

Since

C++11

A weak_ptr provides a safe alternative to a raw pointer when you want a non-owning reference to an object that is managed by a shared_ptr.

Unlike a raw pointer, a weak_ptr can be converted to a new shared_ptr that shares ownership with every other shared_ptr that already owns the pointer. In other words you can upgrade from a non-owning "weak" reference to an owning shared_ptr, without having access to any of the existing shared_ptr objects.

Also unlike a raw pointer, a weak_ptr does not become "dangling" after the object it points to has been destroyed. Instead, a weak_ptr becomes expired and can no longer be converted to a shared_ptr that owns the freed pointer, so you cannot accidentally access the pointed-to object after it has been destroyed.

Definition at line 811 of file bits/shared_ptr.h.

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The documentation for this class was generated from the following file:

• bits/shared_ptr.h