What is the difference between mutex and lock guard in C++?

What is the difference between mutex and lock guard in C++?

In C++, a mutex is a synchronization primitive that allows multiple threads to access shared resources safely. A lock guard, on the other hand, is a wrapper around a mutex that automatically manages the locking and unlocking of the mutex, ensuring that it is released when the lock guard goes out of scope.

Can you give an example of how to use a lock guard?

Sure! Here's a simple example:

#include <iostream>
#include <mutex>

std::mutex mtx;

void safePrint() {
    std::lock_guard<std::mutex> lock(mtx);
    std::cout << "Thread-safe printing!" << std::endl;
}

In this example, std::lock_guard locks the mutex mtx when created and automatically unlocks it when it goes out of scope.

When should I use a mutex instead of a lock guard?

You should use a mutex directly when you need more control over the locking mechanism, such as when you want to lock and unlock the mutex at different points in your code. Use a lock guard for simpler cases where you want automatic management of the mutex's lifetime.

Are there any performance differences between them?

Yes, using a lock guard can be more efficient because it reduces the risk of forgetting to unlock the mutex, which can lead to deadlocks. However, if you need to lock and unlock a mutex multiple times in a function, managing the mutex directly might be more appropriate.