Std::shared_ptr::unique (3) Linux Manual Page

std::shared_ptr<T>::unique – std::shared_ptr<T>::unique

Synopsis

bool unique() const noexcept; (deprecated in C++17)
(removed in C++20)
Checks if *this is the only shared_ptr instance managing the current object, i.e. whether use_count() == 1.

Parameters

(none)

Return value

true if *this is the only shared_ptr instance managing the current object, false otherwise.

Notes

This function was deprecated in C++17 and removed in C++20 because use_count is only an approximation in multithreaded environment (see Notes in use_count)

Example

// Run this code

#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';
}

Output:

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

std::shared_ptr::unique (3) Linux Manual Page