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std::shared_ptr::unique

STD：：共享[医]PTR：：独特

bool unique() const noexcept;​(deprecated)

检查*this是唯一shared_ptr实例管理当前对象，即use_count() == 1...

参数

%280%29

返回值

true如果*this是唯一shared_ptr实例管理当前对象，false否则。

例外

noexcept规格：

noexcept

注记

此函数在C++17中不再受欢迎，因为use_count只是多线程环境中的近似。

例

二次

#include <memory> 
#include <iostream> 
 
int main() 
{ 
    auto sp1 = std::make_shared<int>(5
    std::cout << std::boolalpha;
    std::cout << "sp1.unique() == " << sp1.unique() << '\n'; 
 
    std::shared_ptr<int> sp2 = sp1; 
    std::cout << "sp1.unique() == " << sp1.unique() << '\n'; 
}

二次

产出：

二次

sp1.unique() == true
sp1.unique() == false

二次

另见

use_countreturns the number of shared_ptr objects referring to the same managed object (public member function)

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在CreativeCommonsAttribution下授权-ShareAlike未移植许可v3.0。

http：//en.cppreference.com/w/cpp/Memory/Shared[医]PTR/唯一

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