.TH "std::shared_ptr< _Tp >" 3cxx "Tue Jul 18 2023" "libstdc++" \" -*- nroff -*-
.ad l
.nh
.SH NAME
std::shared_ptr< _Tp > \- A smart pointer with reference-counted copy semantics\&.  

.SH SYNOPSIS
.br
.PP
.PP
\fC#include <shared_ptr\&.h>\fP
.PP
Inherits std::__shared_ptr< _Tp, _Lp >\&.
.SS "Public Types"

.in +1c
.ti -1c
.RI "using \fBelement_type\fP = typename __shared_ptr< _Tp >::element_type"
.br
.RI "The type pointed to by the stored pointer, remove_extent_t<_Tp> "
.in -1c
.SS "Public Member Functions"

.in +1c
.ti -1c
.RI "constexpr \fBshared_ptr\fP () noexcept"
.br
.RI "Construct an empty shared_ptr\&. "
.ti -1c
.RI "template<typename _Yp , typename  = _Constructible<_Yp*>> \fBshared_ptr\fP (_Yp *__p)"
.br
.RI "Construct a shared_ptr that owns the pointer \fI__p\fP\&. "
.ti -1c
.RI "template<typename _Yp , typename _Deleter , typename  = _Constructible<_Yp*, _Deleter>> \fBshared_ptr\fP (_Yp *__p, _Deleter __d)"
.br
.RI "Construct a shared_ptr that owns the pointer \fI__p\fP and the deleter \fI__d\fP\&. "
.ti -1c
.RI "template<typename _Yp , typename _Deleter , typename _Alloc , typename  = _Constructible<_Yp*, _Deleter, _Alloc>> \fBshared_ptr\fP (_Yp *__p, _Deleter __d, _Alloc __a)"
.br
.RI "Construct a shared_ptr that owns the pointer \fI__p\fP and the deleter \fI__d\fP\&. "
.ti -1c
.RI "\fBshared_ptr\fP (const \fBshared_ptr\fP &) noexcept=default"
.br
.RI "Copy constructor\&. "
.ti -1c
.RI "template<typename _Yp , typename  = _Constructible<const shared_ptr<_Yp>&>> \fBshared_ptr\fP (const \fBshared_ptr\fP< _Yp > &__r) noexcept"
.br
.RI "If \fI__r\fP is empty, constructs an empty shared_ptr; otherwise construct a shared_ptr that shares ownership with \fI__r\fP\&. "
.ti -1c
.RI "template<typename _Yp > \fBshared_ptr\fP (const \fBshared_ptr\fP< _Yp > &__r, \fBelement_type\fP *__p) noexcept"
.br
.RI "Constructs a \fCshared_ptr\fP instance that stores \fC__p\fP and shares ownership with \fC__r\fP\&. "
.ti -1c
.RI "template<typename _Yp , typename  = _Constructible<const weak_ptr<_Yp>&>> \fBshared_ptr\fP (const \fBweak_ptr\fP< _Yp > &__r)"
.br
.RI "Constructs a shared_ptr that shares ownership with \fI__r\fP and stores a copy of the pointer stored in \fI__r\fP\&. "
.ti -1c
.RI "template<typename _Deleter > \fBshared_ptr\fP (nullptr_t __p, _Deleter __d)"
.br
.RI "Construct a shared_ptr that owns a null pointer and the deleter \fI__d\fP\&. "
.ti -1c
.RI "template<typename _Deleter , typename _Alloc > \fBshared_ptr\fP (nullptr_t __p, _Deleter __d, _Alloc __a)"
.br
.RI "Construct a shared_ptr that owns a null pointer and the deleter \fI__d\fP\&. "
.ti -1c
.RI "constexpr \fBshared_ptr\fP (nullptr_t) noexcept"
.br
.RI "Construct an empty shared_ptr\&. "
.ti -1c
.RI "\fBshared_ptr\fP (\fBshared_ptr\fP &&__r) noexcept"
.br
.RI "Move-constructs a shared_ptr instance from \fI__r\fP\&. "
.ti -1c
.RI "template<typename _Yp , typename  = _Constructible<shared_ptr<_Yp>>> \fBshared_ptr\fP (\fBshared_ptr\fP< _Yp > &&__r) noexcept"
.br
.RI "Move-constructs a shared_ptr instance from \fI__r\fP\&. "
.ti -1c
.RI "template<typename _Tp1 , typename > \fBshared_ptr\fP (\fBstd::auto_ptr\fP< _Tp1 > &&__r)"
.br
.ti -1c
.RI "template<typename _Yp , typename _Del , typename  = _Constructible<unique_ptr<_Yp, _Del>>> \fBshared_ptr\fP (\fBunique_ptr\fP< _Yp, _Del > &&__r)"
.br
.ti -1c
.RI "\fBelement_type\fP * \fBget\fP () const noexcept"
.br
.RI "Return the stored pointer\&. "
.ti -1c
.RI "\fBoperator bool\fP () const"
.br
.RI "Return true if the stored pointer is not null\&. "
.ti -1c
.RI "\fBelement_type\fP & \fBoperator*\fP () const noexcept"
.br
.ti -1c
.RI "\fBelement_type\fP * \fBoperator\->\fP () const noexcept"
.br
.ti -1c
.RI "\fBshared_ptr\fP & \fBoperator=\fP (const \fBshared_ptr\fP &) noexcept=default"
.br
.ti -1c
.RI "template<typename _Yp > _Assignable< const \fBshared_ptr\fP< _Yp > & > \fBoperator=\fP (const \fBshared_ptr\fP< _Yp > &__r) noexcept"
.br
.ti -1c
.RI "\fBshared_ptr\fP & \fBoperator=\fP (\fBshared_ptr\fP &&__r) noexcept"
.br
.ti -1c
.RI "template<class _Yp > _Assignable< \fBshared_ptr\fP< _Yp > > \fBoperator=\fP (\fBshared_ptr\fP< _Yp > &&__r) noexcept"
.br
.ti -1c
.RI "template<typename _Yp , typename _Del > _Assignable< \fBunique_ptr\fP< _Yp, _Del > > \fBoperator=\fP (\fBunique_ptr\fP< _Yp, _Del > &&__r)"
.br
.ti -1c
.RI "void \fBreset\fP () noexcept"
.br
.ti -1c
.RI "template<typename _Yp > _SafeConv< _Yp > \fBreset\fP (_Yp *__p)"
.br
.ti -1c
.RI "template<typename _Yp , typename _Deleter > _SafeConv< _Yp > \fBreset\fP (_Yp *__p, _Deleter __d)"
.br
.ti -1c
.RI "template<typename _Yp , typename _Deleter , typename _Alloc > _SafeConv< _Yp > \fBreset\fP (_Yp *__p, _Deleter __d, _Alloc __a)"
.br
.ti -1c
.RI "void \fBswap\fP (__shared_ptr< _Tp, _Lp > &__other) noexcept"
.br
.RI "Exchange both the owned pointer and the stored pointer\&. "
.ti -1c
.RI "bool \fBunique\fP () const noexcept"
.br
.RI "Return true if use_count() == 1\&. "
.ti -1c
.RI "long \fBuse_count\fP () const noexcept"
.br
.RI "If *this owns a pointer, return the number of owners, otherwise zero\&. "
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp1 > bool \fBowner_before\fP (__shared_ptr< _Tp1, _Lp > const &__rhs) const noexcept"
.br
.RI "Define an ordering based on ownership\&. "
.ti -1c
.RI "template<typename _Tp1 > bool \fBowner_before\fP (__weak_ptr< _Tp1, _Lp > const &__rhs) const noexcept"
.br
.RI "Define an ordering based on ownership\&. "
.in -1c
.in -1c
.SS "Friends"

.in +1c
.ti -1c
.RI "template<typename _Yp , typename _Alloc , typename\&.\&.\&. _Args> \fBshared_ptr\fP< _Yp > \fBallocate_shared\fP (const _Alloc &__a, _Args &&\&.\&.\&. __args)"
.br
.ti -1c
.RI "class \fBweak_ptr< _Tp >\fP"
.br
.in -1c
.SS "Related Functions"
(Note that these are not member functions\&.) 
.in +1c
.ti -1c
.RI "template<typename _Del , typename _Tp > _Del * \fBget_deleter\fP (const \fBshared_ptr\fP< _Tp > &__p) noexcept"
.br
.RI "20\&.7\&.2\&.2\&.10 shared_ptr get_deleter "
.ti -1c
.RI "template<typename _Ch , typename _Tr , typename _Tp , _Lock_policy _Lp> \fBstd::basic_ostream\fP< _Ch, _Tr > & \fBoperator<<\fP (\fBstd::basic_ostream\fP< _Ch, _Tr > &__os, const __shared_ptr< _Tp, _Lp > &__p)"
.br
.RI "Write the stored pointer to an ostream\&. "
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp , typename _Up > bool \fBoperator==\fP (const \fBshared_ptr\fP< _Tp > &__a, const \fBshared_ptr\fP< _Up > &__b) noexcept"
.br
.ti -1c
.RI "template<typename _Tp > bool \fBoperator==\fP (const \fBshared_ptr\fP< _Tp > &__a, nullptr_t) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator==\fP (nullptr_t, const \fBshared_ptr\fP< _Tp > &__a) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp , typename _Up > bool \fBoperator!=\fP (const \fBshared_ptr\fP< _Tp > &__a, const \fBshared_ptr\fP< _Up > &__b) noexcept"
.br
.RI "Inequality operator for shared_ptr objects, compares the stored pointers\&. "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator!=\fP (const \fBshared_ptr\fP< _Tp > &__a, nullptr_t) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator!=\fP (nullptr_t, const \fBshared_ptr\fP< _Tp > &__a) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp , typename _Up > bool \fBoperator<\fP (const \fBshared_ptr\fP< _Tp > &__a, const \fBshared_ptr\fP< _Up > &__b) noexcept"
.br
.RI "Relational operator for shared_ptr objects, compares the stored pointers\&. "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator<\fP (const \fBshared_ptr\fP< _Tp > &__a, nullptr_t) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator<\fP (nullptr_t, const \fBshared_ptr\fP< _Tp > &__a) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp , typename _Up > bool \fBoperator<=\fP (const \fBshared_ptr\fP< _Tp > &__a, const \fBshared_ptr\fP< _Up > &__b) noexcept"
.br
.RI "Relational operator for shared_ptr objects, compares the stored pointers\&. "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator<=\fP (const \fBshared_ptr\fP< _Tp > &__a, nullptr_t) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator<=\fP (nullptr_t, const \fBshared_ptr\fP< _Tp > &__a) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp , typename _Up > bool \fBoperator>\fP (const \fBshared_ptr\fP< _Tp > &__a, const \fBshared_ptr\fP< _Up > &__b) noexcept"
.br
.RI "Relational operator for shared_ptr objects, compares the stored pointers\&. "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator>\fP (const \fBshared_ptr\fP< _Tp > &__a, nullptr_t) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator>\fP (nullptr_t, const \fBshared_ptr\fP< _Tp > &__a) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp , typename _Up > bool \fBoperator>=\fP (const \fBshared_ptr\fP< _Tp > &__a, const \fBshared_ptr\fP< _Up > &__b) noexcept"
.br
.RI "Relational operator for shared_ptr objects, compares the stored pointers\&. "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator>=\fP (const \fBshared_ptr\fP< _Tp > &__a, nullptr_t) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > bool \fBoperator>=\fP (nullptr_t, const \fBshared_ptr\fP< _Tp > &__a) noexcept"
.br
.RI "shared_ptr comparison with nullptr "
.ti -1c
.RI "template<typename _Tp > void \fBswap\fP (\fBshared_ptr\fP< _Tp > &__a, \fBshared_ptr\fP< _Tp > &__b) noexcept"
.br
.RI "Swap overload for shared_ptr\&. "
.ti -1c
.RI "template<typename _Tp , typename _Up > \fBshared_ptr\fP< _Tp > \fBstatic_pointer_cast\fP (const \fBshared_ptr\fP< _Up > &__r) noexcept"
.br
.RI "Convert type of \fCshared_ptr\fP, via \fCstatic_cast\fP "
.ti -1c
.RI "template<typename _Tp , typename _Up > \fBshared_ptr\fP< _Tp > \fBconst_pointer_cast\fP (const \fBshared_ptr\fP< _Up > &__r) noexcept"
.br
.RI "Convert type of \fCshared_ptr\fP, via \fCconst_cast\fP "
.ti -1c
.RI "template<typename _Tp , typename _Up > \fBshared_ptr\fP< _Tp > \fBdynamic_pointer_cast\fP (const \fBshared_ptr\fP< _Up > &__r) noexcept"
.br
.RI "Convert type of \fCshared_ptr\fP, via \fCdynamic_cast\fP "
.in -1c
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp , typename _Alloc , typename\&.\&.\&. _Args> \fBshared_ptr\fP< _Tp > \fBallocate_shared\fP (const _Alloc &__a, _Args &&\&.\&.\&. __args)"
.br
.RI "Create an object that is owned by a shared_ptr\&. "
.ti -1c
.RI "template<typename _Tp , typename\&.\&.\&. _Args> \fBshared_ptr\fP< _Tp > \fBmake_shared\fP (_Args &&\&.\&.\&. __args)"
.br
.RI "Create an object that is owned by a shared_ptr\&. "
.in -1c
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp , _Lock_policy _Lp> bool \fBatomic_is_lock_free\fP (const __shared_ptr< _Tp, _Lp > *__p)"
.br
.RI "Report whether shared_ptr atomic operations are lock-free\&. "
.in -1c
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp > \fBshared_ptr\fP< _Tp > \fBatomic_load_explicit\fP (const \fBshared_ptr\fP< _Tp > *__p, \fBmemory_order\fP)"
.br
.RI "Atomic load for shared_ptr objects\&. "
.in -1c
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp > void \fBatomic_store_explicit\fP (\fBshared_ptr\fP< _Tp > *__p, \fBshared_ptr\fP< _Tp > __r, \fBmemory_order\fP)"
.br
.RI "Atomic store for shared_ptr objects\&. "
.in -1c
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp > \fBshared_ptr\fP< _Tp > \fBatomic_exchange_explicit\fP (\fBshared_ptr\fP< _Tp > *__p, \fBshared_ptr\fP< _Tp > __r, \fBmemory_order\fP)"
.br
.RI "Atomic exchange for shared_ptr objects\&. "
.in -1c
.in -1c
.PP
.RI "\fB\fP"
.br

.in +1c
.in +1c
.ti -1c
.RI "template<typename _Tp > bool \fBatomic_compare_exchange_strong_explicit\fP (\fBshared_ptr\fP< _Tp > *__p, \fBshared_ptr\fP< _Tp > *__v, \fBshared_ptr\fP< _Tp > __w, \fBmemory_order\fP, \fBmemory_order\fP)"
.br
.RI "Atomic compare-and-swap for shared_ptr objects\&. "
.in -1c
.in -1c
.SH "Detailed Description"
.PP 

.SS "template<typename _Tp>
.br
class std::shared_ptr< _Tp >"A smart pointer with reference-counted copy semantics\&. 

A \fCshared_ptr\fP object is either empty or \fIowns\fP a pointer passed to the constructor\&. Copies of a \fCshared_ptr\fP share ownership of the same pointer\&. When the last \fCshared_ptr\fP that owns the pointer is destroyed or reset, the owned pointer is freed (either by \fCdelete\fP or by invoking a custom deleter that was passed to the constructor)\&.
.PP
A \fCshared_ptr\fP also stores another pointer, which is usually (but not always) the same pointer as it owns\&. The stored pointer can be retrieved by calling the \fCget()\fP member function\&.
.PP
The equality and relational operators for \fCshared_ptr\fP only compare the stored pointer returned by \fCget()\fP, not the owned pointer\&. To test whether two \fCshared_ptr\fP objects share ownership of the same pointer see \fCstd::shared_ptr::owner_before\fP and \fCstd::owner_less\fP\&. 
.SH "Member Typedef Documentation"
.PP 
.SS "template<typename _Tp > using \fBstd::shared_ptr\fP< _Tp >::element_type =  typename __shared_ptr<_Tp>::element_type"

.PP
The type pointed to by the stored pointer, remove_extent_t<_Tp> 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "template<typename _Tp > constexpr \fBstd::shared_ptr\fP< _Tp >::shared_ptr ()\fC [inline]\fP, \fC [constexpr]\fP, \fC [noexcept]\fP"

.PP
Construct an empty shared_ptr\&. 
.PP
\fBPostcondition\fP
.RS 4
use_count()==0 && get()==0 
.RE
.PP

.SS "template<typename _Tp > \fBstd::shared_ptr\fP< _Tp >::shared_ptr (const \fBshared_ptr\fP< _Tp > &)\fC [default]\fP, \fC [noexcept]\fP"

.PP
Copy constructor\&. 
.SS "template<typename _Tp > template<typename _Yp , typename  = _Constructible<_Yp*>> \fBstd::shared_ptr\fP< _Tp >::shared_ptr (_Yp * __p)\fC [inline]\fP, \fC [explicit]\fP"

.PP
Construct a shared_ptr that owns the pointer \fI__p\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__p\fP A pointer that is convertible to element_type*\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
use_count() == 1 && get() == __p 
.RE
.PP
\fBExceptions\fP
.RS 4
\fIstd::bad_alloc,in\fP which case \fCdelete\fP \fI__p\fP is called\&. 
.RE
.PP

.SS "template<typename _Tp > template<typename _Yp , typename _Deleter , typename  = _Constructible<_Yp*, _Deleter>> \fBstd::shared_ptr\fP< _Tp >::shared_ptr (_Yp * __p, _Deleter __d)\fC [inline]\fP"

.PP
Construct a shared_ptr that owns the pointer \fI__p\fP and the deleter \fI__d\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__p\fP A pointer\&. 
.br
\fI__d\fP A deleter\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
use_count() == 1 && get() == __p 
.RE
.PP
\fBExceptions\fP
.RS 4
\fIstd::bad_alloc,in\fP which case \fI__d(__p)\fP is called\&.
.RE
.PP
Requirements: _Deleter's copy constructor and destructor must not throw
.PP
__shared_ptr will release __p by calling __d(__p) 
.SS "template<typename _Tp > template<typename _Deleter > \fBstd::shared_ptr\fP< _Tp >::shared_ptr (nullptr_t __p, _Deleter __d)\fC [inline]\fP"

.PP
Construct a shared_ptr that owns a null pointer and the deleter \fI__d\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__p\fP A null pointer constant\&. 
.br
\fI__d\fP A deleter\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
use_count() == 1 && get() == __p 
.RE
.PP
\fBExceptions\fP
.RS 4
\fIstd::bad_alloc,in\fP which case \fI__d(__p)\fP is called\&.
.RE
.PP
Requirements: _Deleter's copy constructor and destructor must not throw
.PP
The last owner will call __d(__p) 
.SS "template<typename _Tp > template<typename _Yp , typename _Deleter , typename _Alloc , typename  = _Constructible<_Yp*, _Deleter, _Alloc>> \fBstd::shared_ptr\fP< _Tp >::shared_ptr (_Yp * __p, _Deleter __d, _Alloc __a)\fC [inline]\fP"

.PP
Construct a shared_ptr that owns the pointer \fI__p\fP and the deleter \fI__d\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__p\fP A pointer\&. 
.br
\fI__d\fP A deleter\&. 
.br
\fI__a\fP An allocator\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
use_count() == 1 && get() == __p 
.RE
.PP
\fBExceptions\fP
.RS 4
\fIstd::bad_alloc,in\fP which case \fI__d(__p)\fP is called\&.
.RE
.PP
Requirements: _Deleter's copy constructor and destructor must not throw _Alloc's copy constructor and destructor must not throw\&.
.PP
__shared_ptr will release __p by calling __d(__p) 
.SS "template<typename _Tp > template<typename _Deleter , typename _Alloc > \fBstd::shared_ptr\fP< _Tp >::shared_ptr (nullptr_t __p, _Deleter __d, _Alloc __a)\fC [inline]\fP"

.PP
Construct a shared_ptr that owns a null pointer and the deleter \fI__d\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__p\fP A null pointer constant\&. 
.br
\fI__d\fP A deleter\&. 
.br
\fI__a\fP An allocator\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
use_count() == 1 && get() == __p 
.RE
.PP
\fBExceptions\fP
.RS 4
\fIstd::bad_alloc,in\fP which case \fI__d(__p)\fP is called\&.
.RE
.PP
Requirements: _Deleter's copy constructor and destructor must not throw _Alloc's copy constructor and destructor must not throw\&.
.PP
The last owner will call __d(__p) 
.SS "template<typename _Tp > template<typename _Yp > \fBstd::shared_ptr\fP< _Tp >::shared_ptr (const \fBshared_ptr\fP< _Yp > & __r, \fBelement_type\fP * __p)\fC [inline]\fP, \fC [noexcept]\fP"

.PP
Constructs a \fCshared_ptr\fP instance that stores \fC__p\fP and shares ownership with \fC__r\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__r\fP A \fCshared_ptr\fP\&. 
.br
\fI__p\fP A pointer that will remain valid while \fC*__r\fP is valid\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
\fCget() == __p && use_count() == __r\&.use_count()\fP
.RE
.PP
This can be used to construct a \fCshared_ptr\fP to a sub-object of an object managed by an existing \fCshared_ptr\fP\&. The complete object will remain valid while any \fCshared_ptr\fP owns it, even if they don't store a pointer to the complete object\&.
.PP
.PP
.nf
shared_ptr<pair<int,int>> pii(new pair<int,int>());
shared_ptr<int> pi(pii, &pii->first);
assert(pii\&.use_count() == 2);
.fi
.PP
 
.SS "template<typename _Tp > template<typename _Yp , typename  = _Constructible<const shared_ptr<_Yp>&>> \fBstd::shared_ptr\fP< _Tp >::shared_ptr (const \fBshared_ptr\fP< _Yp > & __r)\fC [inline]\fP, \fC [noexcept]\fP"

.PP
If \fI__r\fP is empty, constructs an empty shared_ptr; otherwise construct a shared_ptr that shares ownership with \fI__r\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__r\fP A shared_ptr\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
get() == __r\&.get() && use_count() == __r\&.use_count() 
.RE
.PP

.SS "template<typename _Tp > \fBstd::shared_ptr\fP< _Tp >::shared_ptr (\fBshared_ptr\fP< _Tp > && __r)\fC [inline]\fP, \fC [noexcept]\fP"

.PP
Move-constructs a shared_ptr instance from \fI__r\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__r\fP A shared_ptr rvalue\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
*this contains the old value of \fI__r\fP, \fI__r\fP is empty\&. 
.RE
.PP

.SS "template<typename _Tp > template<typename _Yp , typename  = _Constructible<shared_ptr<_Yp>>> \fBstd::shared_ptr\fP< _Tp >::shared_ptr (\fBshared_ptr\fP< _Yp > && __r)\fC [inline]\fP, \fC [noexcept]\fP"

.PP
Move-constructs a shared_ptr instance from \fI__r\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__r\fP A shared_ptr rvalue\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
*this contains the old value of \fI__r\fP, \fI__r\fP is empty\&. 
.RE
.PP

.SS "template<typename _Tp > template<typename _Yp , typename  = _Constructible<const weak_ptr<_Yp>&>> \fBstd::shared_ptr\fP< _Tp >::shared_ptr (const \fBweak_ptr\fP< _Yp > & __r)\fC [inline]\fP, \fC [explicit]\fP"

.PP
Constructs a shared_ptr that shares ownership with \fI__r\fP and stores a copy of the pointer stored in \fI__r\fP\&. 
.PP
\fBParameters\fP
.RS 4
\fI__r\fP A weak_ptr\&. 
.RE
.PP
\fBPostcondition\fP
.RS 4
use_count() == __r\&.use_count() 
.RE
.PP
\fBExceptions\fP
.RS 4
\fIbad_weak_ptr\fP when __r\&.expired(), in which case the constructor has no effect\&. 
.RE
.PP

.SS "template<typename _Tp > constexpr \fBstd::shared_ptr\fP< _Tp >::shared_ptr (nullptr_t)\fC [inline]\fP, \fC [constexpr]\fP, \fC [noexcept]\fP"

.PP
Construct an empty shared_ptr\&. 
.PP
\fBPostcondition\fP
.RS 4
use_count() == 0 && get() == nullptr 
.RE
.PP

.SH "Member Function Documentation"
.PP 
.SS "template<typename _Tp , _Lock_policy _Lp> \fBelement_type\fP * std::__shared_ptr< _Tp, _Lp >::get (void) const\fC [inline]\fP, \fC [noexcept]\fP, \fC [inherited]\fP"

.PP
Return the stored pointer\&. 
.SS "template<typename _Tp , _Lock_policy _Lp> std::__shared_ptr< _Tp, _Lp >::operator bool () const\fC [inline]\fP, \fC [explicit]\fP, \fC [inherited]\fP"

.PP
Return true if the stored pointer is not null\&. 
.SS "template<typename _Tp , _Lock_policy _Lp> template<typename _Tp1 > bool std::__shared_ptr< _Tp, _Lp >::owner_before (__shared_ptr< _Tp1, _Lp > const & __rhs) const\fC [inline]\fP, \fC [noexcept]\fP, \fC [inherited]\fP"

.PP
Define an ordering based on ownership\&. This function defines a strict weak ordering between two shared_ptr or weak_ptr objects, such that one object is less than the other unless they share ownership of the same pointer, or are both empty\&. 
.SS "template<typename _Tp , _Lock_policy _Lp> template<typename _Tp1 > bool std::__shared_ptr< _Tp, _Lp >::owner_before (__weak_ptr< _Tp1, _Lp > const & __rhs) const\fC [inline]\fP, \fC [noexcept]\fP, \fC [inherited]\fP"

.PP
Define an ordering based on ownership\&. This function defines a strict weak ordering between two shared_ptr or weak_ptr objects, such that one object is less than the other unless they share ownership of the same pointer, or are both empty\&. 
.SS "template<typename _Tp , _Lock_policy _Lp> void std::__shared_ptr< _Tp, _Lp >::swap (__shared_ptr< _Tp, _Lp > & __other)\fC [inline]\fP, \fC [noexcept]\fP, \fC [inherited]\fP"

.PP
Exchange both the owned pointer and the stored pointer\&. 
.SS "template<typename _Tp , _Lock_policy _Lp> bool std::__shared_ptr< _Tp, _Lp >::unique () const\fC [inline]\fP, \fC [noexcept]\fP, \fC [inherited]\fP"

.PP
Return true if use_count() == 1\&. 
.SS "template<typename _Tp , _Lock_policy _Lp> long std::__shared_ptr< _Tp, _Lp >::use_count () const\fC [inline]\fP, \fC [noexcept]\fP, \fC [inherited]\fP"

.PP
If *this owns a pointer, return the number of owners, otherwise zero\&. 

.SH "Author"
.PP 
Generated automatically by Doxygen for libstdc++ from the source code\&.