How to use atomic operations in C++ to ensure thread safety?

Using atomic operations in C++ can ensure thread safety, using std::atomic template class and std::atomic_flag class to represent atomic types and Boolean types respectively. Atomic operations are performed through functions such as std::atomic_init(), std::atomic_load(), and std::atomic_store(). In the actual case, atomic operations are used to implement thread-safe counters to ensure thread safety when multiple threads access concurrently, and finally output the correct counter value.

Use atomic operations in C++ to ensure thread safety

In a multi-threaded environment, when multiple threads concurrently access shared data, it may cause Data race issues, resulting in unpredictable results. In order to prevent this situation, you can use the atomic operation mechanism in C++ to ensure thread safety.

Introduction to Atomic Operations

Atomic operations are special instructions used to operate on data in memory to ensure that the operation is performed in an atomic manner, that is, it is either executed in full or not at all. This means that when one thread performs an atomic operation, other threads cannot access the same data at the same time.

Atomic operations in C++

C++11 introduces the <atomic></atomic> header file, which provides various atomic operations, including:

• std::atomic<t></t>: Template class, representing atomic operations of atomic types.
• std::atomic_flag: No-argument atomic flag, indicating Boolean type atomic operation.
• std::atomic_init(), std::atomic_load(), std::atomic_store() and other functions: basic functions of atomic operations.

Practical case: Thread-safe counter

The following is an example of using atomic operations to implement a thread-safe counter:

#include <atomic>
#include <iostream>
#include <thread>

std::atomic<int> counter{0};

void increment_counter() {
  for (int i = 0; i < 1000000; ++i) {
    // 使用原子操作递增计数器
    ++counter;
  }
}

int main() {
  // 创建多个线程并发递增计数器
  std::thread threads[4];
  for (int i = 0; i < 4; ++i) {
    threads[i] = std::thread(increment_counter);
  }

  // 等待所有线程完成
  for (int i = 0; i < 4; ++i) {
    threads[i].join();
  }

  // 打印最终计数器值
  std::cout << "Final counter value: " << counter << std::endl;

  return 0;
}

In this example, we use std::atomic<int></int> Create an atomic integer counter and increment the counter concurrently in multiple threads. Due to the use of atomic operations, even if multiple threads access the counter at the same time, thread safety will be guaranteed and the correct counter value will eventually be output.

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