std::shared_ptr

 

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关系运算符 Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

双和元组 Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

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piecewise_construct （C++11）

掉期，远期和移动 Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

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低级别的内存管理
分配器 Original: Allocators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
allocator
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allocator_arg_t （C++11）
allocator_arg （C++11）
uses_allocator （C++11）
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未初始化的存储空间 Original: Uninitialized storage The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
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智能指针 Original: Smart pointers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
unique_ptr （C++11）
shared_ptr （C++11）
weak_ptr （C++11）
auto_ptr （过时了）
owner_less （C++11）
enable_shared_from_this （C++11）
bad_weak_ptr （C++11）
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malloc calloc	realloc free

 

std::shared_ptr

成员函数 Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

shared_ptr::shared_ptr

shared_ptr::~shared_ptr

shared_ptr::operator=

修饰符 Original: Modifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

shared_ptr::reset

shared_ptr::swap

观察员 Original: Observers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

shared_ptr::get

shared_ptr::operator* shared_ptr::operator->

shared_ptr::use_count

shared_ptr::unique

shared_ptr::operator bool

shared_ptr::owner_before

非成员函数 Original: Non-member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

std::swap

make_shared

allocate_shared

static_pointer_cast dynamic_pointer_cast const_pointer_cast

get_deleter

operator== operator|= operator< operator<= operator> operator>=

operator<<

atomic_is_lock_free atomic_load atomic_load_explicit atomic_store atomic_store_explicit atomic_exchange atomic_exchange_explicit

std::hash

 

Defined in header <memory>
template< class T > class shared_ptr;		（C++11 起）

std::shared_ptr 是通过指针保持某个对象的共享拥有权的智能指针。若干个 shared_ptr 对象可以拥有同一个对象；最后一个指向该对象的 shared_ptr 被销毁或重置时，该对象被销毁。销毁该对象时使用的是 delete 表达式或者是在构造 shared_ptr 时传入的自定义删除器（deleter）。

shared_ptr 也可以不拥有对象，称作空（empty）。

shared_ptr 满足 CopyConstructible 和 CopyAssignable 的要求。

成员类型

成员类型	定义
element_type	T

成员函数

(constructor)	constructs new shared_ptr （公共成员函数）
(destructor)	解构拥有的对象如果没有更多shared_ptrs的的链接 Original: destructs the owned object if no more shared_ptrs link to it The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
operator=	分配shared_ptr Original: assigns the shared_ptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
修饰符 Original: Modifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
reset	取代管理的对象 Original: replaces the managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
swap	掉期所管理的对象 Original: swaps the managed objects The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
观察员 Original: Observers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
get	返回一个指针，指向被管理对象 Original: returns a pointer to the managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
operator* operator->	解引用指针到的管理对象 Original: dereferences pointer to the managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
use_count	返回shared_ptr对象指的是在同一个管理对象的数量 Original: returns the number of shared_ptr objects referring to the same managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
unique	检查是否被管理对象的管理仅由当前shared_ptr的实例 Original: checks whether the managed object is managed only by the current shared_ptr instance The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
operator bool	检查是否有相关的管理对象 Original: checks if there is associated managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）
owner_before	业主基于订购的共享指针 Original: provides owner-based ordering of shared pointers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （公共成员函数）

非成员函数

make_shared	创建一个共享管理一个新的对象的指针，该指针 Original: creates a shared pointer that manages a new object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
allocate_shared	创建一个共享指针管理使用分配器分配一个新的对象 Original: creates a shared pointer that manages a new object allocated using an allocator The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
static_pointer_cast dynamic_pointer_cast const_pointer_cast	适用于static_cast，dynamic_cast或const_cast被管理对象的类型 Original: applies static_cast, dynamic_cast or const_cast to the type of the managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
get_deleter	返回指定类型的删除，如果拥有 Original: returns the deleter of specified type, if owned The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
operator== operator!= operator< operator<= operator> operator>=	与另一个shared_ptr或nullptr Original: compares with another shared_ptr or with nullptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
operator<<	托管指针的值输出到输出流中 Original: outputs the value of the managed pointer to an output stream The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
std::swap(std::shared_ptr) （C++11）	专业的std::swap算法 Original: specializes the std::swap algorithm The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）

std::atomic_is_lock_free(std::shared_ptr) std::atomic_load(std::shared_ptr) std::atomic_load_explicit(std::shared_ptr) std::atomic_store(std::shared_ptr) std::atomic_store_explicit(std::shared_ptr) std::atomic_exchange(std::shared_ptr) std::atomic_exchange_explicit(std::shared_ptr) std::atomic_compare_exchange_weak(std::shared_ptr) std::atomic_compare_exchange_strong(std::shared_ptr) std::atomic_compare_exchange_weak_explicit(std::shared_ptr) std::atomic_compare_exchange_strong_explicit(std::shared_ptr)

专业原子操作 Original: specializes atomic operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）

Helper类

std::hash<std::shared_ptr> （C++11）	std::shared_ptr的哈希支持 Original: hash support for std::shared_ptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （类模板专业化）

实现说明

在典型的实现中，std::shared_ptr 只保存两个指针：

• 指向被管理对象的指针
• 指向控制块（control block）的指针

控制块是一个动态分配的对象，其中包含：

• 指向被管理对象的指针或被管理对象本身
• 删除器
• 分配器（allocator）
• 拥有被管理对象的 shared_ptr 的数量
• 引用被管理对象的 weak_ptr 的数量

通过 std::make_shared 和 std::allocate_shared 创建 shared_ptr 时，控制块将被管理对象本身作为其数据成员；而通过构造函数创建 shared_ptr 时则保存指针。

shared_ptr 持有的指针是通过 get() 返回的；而控制块所持有的指针/对象则是最终引用计数归零时会被删除的那个。两者并不一定相等。

shared_ptr 的析构函数会将控制块中的 shared_ptr 计数器减一，如果减至零，控制块就会调用被管理对象的析构函数。但控制块本身直到 std::weak_ptr 计数器同样归零时才会释放。