What are some examples of mutex deadlocks?

What are some examples of mutex deadlocks?

Mutex deadlocks occur when two or more threads are blocked forever, each waiting on the other. For example, Thread A locks Resource 1 and waits for Resource 2, while Thread B locks Resource 2 and waits for Resource 1.

Can you give me a code example of this?

Sure! Here's a simple example in C++:

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

std::mutex mutex1;
std::mutex mutex2;

void threadA() {
    std::lock_guard<std::mutex> lock1(mutex1);
    std::this_thread::sleep_for(std::chrono::milliseconds(100));
    std::lock_guard<std::mutex> lock2(mutex2);
}

void threadB() {
    std::lock_guard<std::mutex> lock2(mutex2);
    std::this_thread::sleep_for(std::chrono::milliseconds(100));
    std::lock_guard<std::mutex> lock1(mutex1);
}

int main() {
    std::thread t1(threadA);
    std::thread t2(threadB);
    t1.join();
    t2.join();
    return 0;
}

This code can lead to a deadlock situation.

How can I prevent deadlocks in my code?

To prevent deadlocks, you can use techniques like acquiring locks in a consistent order, using timeout mechanisms, or employing lock-free data structures.