std::weak_ptr< _Tp >(3cxx) std::weak_ptr< _Tp >(3cxx)
NAME
std::weak_ptr< _Tp > - A non-owning observer for a pointer owned by a
shared_ptr.
SYNOPSIS
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
Swap overload for weak_ptr.
Detailed Description
template<typename _Tp>
class std::weak_ptr< _Tp >" A non-owning observer for a pointer owned
by a shared_ptr.
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.
Author
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libstdc++ Sat May 13 2023 std::weak_ptr< _Tp >(3cxx)
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