What is a mutex deadlock in C++?

Can you explain what a mutex deadlock is in C++?

A mutex deadlock occurs when two or more threads are blocked forever, each waiting for the other to release a mutex.

How can I prevent deadlocks in my C++ code?

You can prevent deadlocks by using a lock hierarchy, avoiding nested locks, or using timeout mechanisms.

What are some common scenarios that lead to deadlocks?

Common scenarios include circular wait conditions, where two or more threads hold locks and wait for each other.

Can you provide a code example of a deadlock?

Sure! Here's a simple example:

std::mutex m1, m2;

void thread1() {
    std::lock_guard<std::mutex> lock1(m1);
    std::this_thread::sleep_for(std::chrono::milliseconds(1));
    std::lock_guard<std::mutex> lock2(m2);
}

void thread2() {
    std::lock_guard<std::mutex> lock2(m2);
    std::this_thread::sleep_for(std::chrono::milliseconds(1));
    std::lock_guard<std::mutex> lock1(m1);
}

In this example, thread1 locks m1 and waits for m2, while thread2 locks m2 and waits for m1.