Implementation of mutual exclusion and critical section of C++ functions in concurrent programming?

In concurrent programming, mutual exclusion and critical sections are used to prevent data competition. Mutex is a data structure that allows only one thread to access a shared resource at a time. The specific implementation is as follows: Define a Mutex class with an atomic tag. Use the test_and_set() method to lock and the clear() method to unlock. The critical section is a section of code that can only be executed by one thread at a time. The specific implementation is as follows: declare a mutex. Use the lock_guard wrapper to access shared resources in critical sections.

Mutual exclusion and critical section implementation of C functions in concurrent programming

In concurrent programming, when multiple threads access shared resources at the same time, it is necessary Prevent data races and ensure data consistency. Mutexes and critical sections are two common ways to achieve this.

Mutual exclusion

Mutual exclusion is a data structure that ensures that only one thread can access a shared resource at a time. Mutual exclusion is usually implemented using the following method:

class Mutex {
private:
    std::atomic_flag flag;

public:
    void lock() {
        while (flag.test_and_set(std::memory_order_acquire));
    }

    void unlock() {
        flag.clear(std::memory_order_release);
    }
};

Critical Section

A critical section is a section of code that only one thread can execute at any given moment. The implementation of critical sections usually uses the following syntax:

std::mutex mutex;

void critical_section() {
    std::lock_guard<std::mutex> lock(mutex);
    // 共享资源的访问
}

Practical case

Consider a program that contains a shared counter that can be incremented by multiple threads at the same time. Use a mutual exclusion to protect the counter:

Mutex counter_mutex;
int counter = 0;

void increment_counter() {
    counter_mutex.lock();
    counter++;
    counter_mutex.unlock();
}

Use a critical section to protect the counter:

std::mutex counter_mutex;

void increment_counter() {
    std::lock_guard<std::mutex> lock(counter_mutex);
    counter++;
}

Using a mutual exclusion or critical section can ensure that only one thread modifies the counter at the same time, thus preventing data races. The right choice depends on the performance and complexity requirements of your specific application.

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