What is the difference between lock_guard and unique_lock in C++?

What is the difference between lock_guard and unique_lock in C++?

The main difference is that lock_guard is a simple RAII wrapper for mutexes, while unique_lock offers more flexibility.

Can you explain what RAII means?

RAII stands for Resource Acquisition Is Initialization. It ensures that resources are properly released when they go out of scope.

When should I use unique_lock instead of lock_guard?

Use unique_lock when you need to lock and unlock a mutex multiple times or when you need to transfer ownership.

Are there any performance differences between them?

Yes, lock_guard is generally more lightweight and faster, while unique_lock has some overhead due to its additional features.

Can you give an example of using both in code?

Sure! Here's a simple example:

std::mutex m;

void example() {
    lock_guard<std::mutex> guard(m); // Automatically locks the mutex
    // critical section
}

void example2() {
    unique_lock<std::mutex> lock(m);
    // critical section
    lock.unlock(); // Manually unlocks
}