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std::atomic_ref<T>:: atomic_ref

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explicit atomic_ref ( T & obj ) ;
(1) (C++26부터 constexpr)
atomic_ref ( const atomic_ref & ref ) noexcept ;
(2) (C++26부터 constexpr)

새로운 atomic_ref 객체를 생성합니다.

1) 객체 obj 를 참조하는 atomic_ref 객체를 생성합니다.
만약 obj 가 required_alignment 에 정렬되지 않으면, 동작은 정의되지 않습니다.
2) atomic_ref 객체를 생성하며, 이 객체는 ref 가 참조하는 객체를 참조합니다.

매개변수

obj - 참조할 객체
ref - 복사할 다른 atomic_ref 객체

예제

이 프로그램은 여러 스레드를 사용하여 컨테이너의 값을 증가시킵니다. 그런 다음 최종 합계를 출력합니다. 비원자적 접근은 데이터 경쟁으로 인해 일부 연산 결과가 "손실"될 수 있습니다.

이 코드 실행 
#include <atomic>
#include <iostream>
#include <numeric>
#include <thread>
#include <vector>
int main()
{
    using Data = std::vector<char>;
    auto inc_atomically = [](Data& data)
    {
        for (Data::value_type& x : data)
        {
            auto xx = std::atomic_ref<Data::value_type>(x);
            ++xx; // atomic read-modify-write
        }
    };
    auto inc_directly = [](Data& data)
    {
        for (Data::value_type& x : data)
            ++x;
    };
    auto test_run = [](const auto Fun)
    {
        Data data(10'000'000);
        {
            std::jthread j1{Fun, std::ref(data)};
            std::jthread j2{Fun, std::ref(data)};
            std::jthread j3{Fun, std::ref(data)};
            std::jthread j4{Fun, std::ref(data)};
        }
        std::cout << "sum = " << std::accumulate(cbegin(data), cend(data), 0) << '\n';
    };
    test_run(inc_atomically);
    test_run(inc_directly);
}

가능한 출력: 

sum = 40000000
sum = 39994973