When should I use conditional variables in C++?

When should I use conditional variables in C++?

Conditional variables are used in C++ for synchronizing threads, allowing one thread to wait for a condition to be true before proceeding.

Can you give me an example of how to implement them?

Sure! You can use std::condition_variable along with a mutex. Here's a simple example:

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

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

void worker() {
    std::unique_lock<std::mutex> lock(m);
    cv.wait(lock, [] { return ready; }); // Wait until ready is true
    std::cout << "Worker thread proceeding..." << std::endl;
}

int main() {
    std::thread t(worker);
    std::this_thread::sleep_for(std::chrono::seconds(1));
    {
        std::lock_guard<std::mutex> lock(m);
        ready = true;
    }
    cv.notify_one(); // Notify the worker thread
    t.join();
    return 0;
}

What are the advantages of using conditional variables?

They help avoid busy waiting, reduce CPU usage, and allow threads to sleep until a specific condition is met, improving efficiency.