What are mutexes and how do they work in multithreading?

What are mutexes and how do they work in multithreading?

Mutexes, or mutual exclusions, are synchronization primitives used to prevent multiple threads from accessing shared resources simultaneously.

Why do I need to use a mutex instead of just letting threads run freely?

Without mutexes, you risk data corruption and unpredictable behavior due to race conditions when multiple threads modify shared data.

Can you give me an example of how to implement a mutex in code?

Sure! In C++, you can use the std::mutex class. Here's a simple example:

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

std::mutex mtx;

void print(int id) {
    mtx.lock();
    std::cout << "Thread " << id << " is running." << std::endl;
    mtx.unlock();
}

int main() {
    std::thread t1(print, 1);
    std::thread t2(print, 2);
    t1.join();
    t2.join();
    return 0;
}

What happens if I forget to unlock a mutex?

If you forget to unlock a mutex, it can lead to deadlocks, where other threads are blocked indefinitely, waiting for the mutex to be released.