What is a mutex in C++?

What is a mutex in C++?

A mutex, or mutual exclusion, is a synchronization primitive used to prevent multiple threads from accessing shared resources simultaneously.

How do I implement a mutex in my C++ code?

You can implement a mutex in C++ using the <mutex> header. Here's a simple example:

#include <iostream>
#include <thread>
#include <mutex>

std::mutex mtx;

void printThreadId(int id) {
    mtx.lock();  // Lock the mutex
    std::cout << "Thread ID: " << id << '\n';
    mtx.unlock();  // Unlock the mutex
}

int main() {
    std::thread threads[5];
    for (int i = 0; i < 5; ++i) {
        threads[i] = std::thread(printThreadId, i);
    }
    for (auto& th : threads) {
        th.join();
    }
    return 0;
}

What happens if I forget to unlock the mutex?

If you forget to unlock the mutex, it can lead to a deadlock situation where other threads are unable to acquire the lock and thus cannot proceed.

Are there alternatives to using mutexes?

Yes, alternatives include using read-write locks, semaphores, or atomic operations, depending on your specific use case.