What is std::condition_variable in C++?

Can you explain what std::condition_variable is in C++?

Sure! std::condition_variable is a synchronization primitive that allows threads to wait until a particular condition occurs.

How do I use std::condition_variable in my code?

You typically use it with std::mutex to protect shared data. You can call wait() to block a thread until notified.

What are the main functions associated with std::condition_variable?

The main functions are wait(), notify_one(), and notify_all(). They help manage thread synchronization effectively.

Can you give me a simple code example?

Certainly! Here's a basic 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; });
    std::cout << "Worker thread is running!" << std::endl;
}

int main() {
    std::thread t(worker);
    { 
        std::lock_guard<std::mutex> lock(m);
        ready = true;
    }
    cv.notify_one();
    t.join();
    return 0;
}