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std::shared_ptr< _Tp >(3) Library Functions Manual std::shared_ptr< _Tp >(3)

NAME

std::shared_ptr< _Tp > -

SYNOPSIS

Inherits std::__shared_ptr< _Tp, _Lp >.

Public Types


typedef _Tp element_type

Public Member Functions


constexpr shared_ptr () noexcept
shared_ptr (const shared_ptr &) noexcept=default
template<typename _Tp1 > shared_ptr (_Tp1 *__p)
template<typename _Tp1 , typename _Deleter > shared_ptr (_Tp1 *__p, _Deleter __d)
template<typename _Deleter > shared_ptr (nullptr_t __p, _Deleter __d)
template<typename _Tp1 , typename _Deleter , typename _Alloc > shared_ptr (_Tp1 *__p, _Deleter __d, _Alloc __a)
template<typename _Deleter , typename _Alloc > shared_ptr (nullptr_t __p, _Deleter __d, _Alloc __a)
template<typename _Tp1 > shared_ptr (const shared_ptr< _Tp1 > &__r, _Tp *__p) noexcept
template<typename _Tp1 , typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> shared_ptr (const shared_ptr< _Tp1 > &__r) noexcept
shared_ptr (shared_ptr &&__r) noexcept
template<typename _Tp1 , typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> shared_ptr (shared_ptr< _Tp1 > &&__r) noexcept
template<typename _Tp1 > shared_ptr (const weak_ptr< _Tp1 > &__r)
template<typename _Tp1 , typename _Del > shared_ptr (std::unique_ptr< _Tp1, _Del > &&__r)
constexpr shared_ptr (nullptr_t __p) noexcept
template<typename _Tp1 > shared_ptr (std::auto_ptr< _Tp1 > &&__r)
_Tp * get () const noexcept
operator bool () const
std::add_lvalue_reference< _Tp >
::type operator* () const noexcept"
_Tp * operator-> () const noexcept
shared_ptr & operator= (const shared_ptr &) noexcept=default
template<typename _Tp1 > shared_ptr & operator= (const shared_ptr< _Tp1 > &__r) noexcept
shared_ptr & operator= (shared_ptr &&__r) noexcept
template<class _Tp1 > shared_ptr & operator= (shared_ptr< _Tp1 > &&__r) noexcept
template<typename _Tp1 , typename _Del > shared_ptr & operator= (std::unique_ptr< _Tp1, _Del > &&__r)
template<typename _Tp1 > bool owner_before (__shared_ptr< _Tp1, _Lp > const &__rhs) const
template<typename _Tp1 > bool owner_before (__weak_ptr< _Tp1, _Lp > const &__rhs) const
void reset () noexcept
template<typename _Tp1 > void reset (_Tp1 *__p)
template<typename _Tp1 , typename _Deleter > void reset (_Tp1 *__p, _Deleter __d)
template<typename _Tp1 , typename _Deleter , typename _Alloc > void reset (_Tp1 *__p, _Deleter __d, _Alloc __a)
void swap (__shared_ptr< _Tp, _Lp > &__other) noexcept
bool unique () const noexcept
long use_count () const noexcept

Friends


template<typename _Tp1 , typename _Alloc , typename... _Args> shared_ptr< _Tp1 > allocate_shared (const _Alloc &__a, _Args &&...__args)

Detailed Description

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

A smart pointer with reference-counted copy semantics.

The object pointed to is deleted when the last shared_ptr pointing to it is destroyed or reset.

Definition at line 93 of file shared_ptr.h.

Constructor & Destructor Documentation

template<typename _Tp> constexpr std::shared_ptr< _Tp >::shared_ptr () [inline], [noexcept]

Construct an empty shared_ptr.

Postcondition:

use_count()==0 && get()==0

Definition at line 100 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 > std::shared_ptr< _Tp >::shared_ptr (_Tp1 *__p) [inline], [explicit]

Construct a shared_ptr that owns the pointer __p.

Parameters:

__p A pointer that is convertible to element_type*.

Postcondition:

use_count() == 1 && get() == __p

Exceptions:

std::bad_alloc,in which case delete __p is called.

Definition at line 112 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 , typename _Deleter > std::shared_ptr< _Tp >::shared_ptr (_Tp1 *__p, _Deleter__d) [inline]

Construct a shared_ptr that owns the pointer __p and the deleter __d.

Parameters:

__p A pointer.
__d A deleter.

Postcondition:

use_count() == 1 && get() == __p

Exceptions:

std::bad_alloc,in which case __d(__p) is called.

Requirements: _Deleter's copy constructor and destructor must not throw

__shared_ptr will release __p by calling __d(__p)

Definition at line 129 of file shared_ptr.h.

template<typename _Tp> template<typename _Deleter > std::shared_ptr< _Tp >::shared_ptr (nullptr_t__p, _Deleter__d) [inline]

Construct a shared_ptr that owns a null pointer and the deleter __d.

Parameters:

__p A null pointer constant.
__d A deleter.

Postcondition:

use_count() == 1 && get() == __p

Exceptions:

std::bad_alloc,in which case __d(__p) is called.

Requirements: _Deleter's copy constructor and destructor must not throw

The last owner will call __d(__p)

Definition at line 146 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 , typename _Deleter , typename _Alloc > std::shared_ptr< _Tp >::shared_ptr (_Tp1 *__p, _Deleter__d, _Alloc__a) [inline]

Construct a shared_ptr that owns the pointer __p and the deleter __d.

Parameters:

__p A pointer.
__d A deleter.
__a An allocator.

Postcondition:

use_count() == 1 && get() == __p

Exceptions:

std::bad_alloc,in which case __d(__p) is called.

Requirements: _Deleter's copy constructor and destructor must not throw _Alloc's copy constructor and destructor must not throw.

__shared_ptr will release __p by calling __d(__p)

Definition at line 165 of file shared_ptr.h.

template<typename _Tp> template<typename _Deleter , typename _Alloc > std::shared_ptr< _Tp >::shared_ptr (nullptr_t__p, _Deleter__d, _Alloc__a) [inline]

Construct a shared_ptr that owns a null pointer and the deleter __d.

Parameters:

__p A null pointer constant.
__d A deleter.
__a An allocator.

Postcondition:

use_count() == 1 && get() == __p

Exceptions:

std::bad_alloc,in which case __d(__p) is called.

Requirements: _Deleter's copy constructor and destructor must not throw _Alloc's copy constructor and destructor must not throw.

The last owner will call __d(__p)

Definition at line 184 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 > std::shared_ptr< _Tp >::shared_ptr (const shared_ptr< _Tp1 > &__r, _Tp *__p) [inline], [noexcept]

Constructs a shared_ptr instance that stores __p and shares ownership with __r.

Parameters:

__r A shared_ptr.
__p A pointer that will remain valid while *__r is valid.

Postcondition:

get() == __p && use_count() == __r.use_count()

This can be used to construct a shared_ptr to a sub-object of an object managed by an existing shared_ptr.

shared_ptr< pair<int,int> > pii(new pair<int,int>());
shared_ptr<int> pi(pii, &pii->first);
assert(pii.use_count() == 2);

Definition at line 206 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 , typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> std::shared_ptr< _Tp >::shared_ptr (const shared_ptr< _Tp1 > &__r) [inline], [noexcept]

If __r is empty, constructs an empty shared_ptr; otherwise construct a shared_ptr that shares ownership with __r.

Parameters:

__r A shared_ptr.

Postcondition:

get() == __r.get() && use_count() == __r.use_count()

Definition at line 218 of file shared_ptr.h.

template<typename _Tp> std::shared_ptr< _Tp >::shared_ptr (shared_ptr< _Tp > &&__r) [inline], [noexcept]

Move-constructs a shared_ptr instance from __r.

Parameters:

__r A shared_ptr rvalue.

Postcondition:

*this contains the old value of __r, __r is empty.

Definition at line 226 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 , typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> std::shared_ptr< _Tp >::shared_ptr (shared_ptr< _Tp1 > &&__r) [inline], [noexcept]

Move-constructs a shared_ptr instance from __r.

Parameters:

__r A shared_ptr rvalue.

Postcondition:

*this contains the old value of __r, __r is empty.

Definition at line 236 of file shared_ptr.h.

template<typename _Tp> template<typename _Tp1 > std::shared_ptr< _Tp >::shared_ptr (const weak_ptr< _Tp1 > &__r) [inline], [explicit]

Constructs a shared_ptr that shares ownership with __r and stores a copy of the pointer stored in __r.

Parameters:

__r A weak_ptr.

Postcondition:

use_count() == __r.use_count()

Exceptions:

bad_weak_ptr when __r.expired(), in which case the constructor has no effect.

Definition at line 248 of file shared_ptr.h.

template<typename _Tp> constexpr std::shared_ptr< _Tp >::shared_ptr (nullptr_t__p) [inline], [noexcept]

Construct an empty shared_ptr.

Parameters:

__p A null pointer constant.

Postcondition:

use_count() == 0 && get() == nullptr

Definition at line 265 of file shared_ptr.h.

Friends And Related Function Documentation

template<typename _Tp> template<typename _Tp1 , typename _Alloc , typename... _Args> shared_ptr<_Tp1> allocate_shared (const _Alloc &__a, _Args &&...__args) [friend]

Create an object that is owned by a shared_ptr.

Parameters:

__a An allocator.
__args Arguments for the _Tp object's constructor.

Returns:

A shared_ptr that owns the newly created object.

Exceptions:

An exception thrown from _Alloc::allocate or from the constructor of _Tp.

A copy of __a will be used to allocate memory for the shared_ptr and the new object.

Definition at line 595 of file shared_ptr.h.

Author

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Tue Sep 29 2020 libstdc++