What are the best practices for using condition variables in programming?

What are the best practices for using condition variables in programming?

Condition variables are crucial for synchronizing threads. Here are some best practices: 1. Always use a mutex with condition variables. 2. Avoid spurious wakeups by using a loop to check the condition. 3. Keep the critical section short to reduce contention.

Can you explain why it's important to use a mutex with condition variables?

Using a mutex ensures that only one thread can access the shared resource at a time, preventing race conditions. It protects the condition check and the signaling process.

What do you mean by spurious wakeups?

Spurious wakeups occur when a thread wakes up from a wait state without being signaled. This is why it's essential to check the condition in a loop after waking up.

How can I implement a condition variable in C++?

In C++, you can use std::condition_variable along with std::mutex. Here's a simple example:

std::mutex mtx;
std::condition_variable cv;
bool ready = false;

void worker() {
    std::unique_lock<std::mutex> lock(mtx);
    while (!ready) cv.wait(lock);
    // Proceed with work
}

void signal() {
    std::lock_guard<std::mutex> lock(mtx);
    ready = true;
    cv.notify_all();
}