What are some examples of condition variables in programming?

What are some examples of condition variables in programming?

Condition variables are synchronization primitives that enable threads to wait until a particular condition occurs. For example, in a producer-consumer scenario, a condition variable can be used to signal when a buffer is empty or full.

Can you give me a code example using condition variables?

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

#include <iostream>
#include <thread>
#include <condition_variable>
#include <queue>

std::queue<int> buffer;
std::mutex mtx;
std::condition_variable cv;

void producer() {
    for (int i = 0; i < 10; ++i) {
        std::unique_lock<std::mutex> lock(mtx);
        buffer.push(i);
        cv.notify_one();
        lock.unlock();
    }
}

void consumer() {
    for (int i = 0; i < 10; ++i) {
        std::unique_lock<std::mutex> lock(mtx);
        cv.wait(lock, []{ return !buffer.empty(); });
        int value = buffer.front();
        buffer.pop();
        lock.unlock();
        std::cout << "Consumed: " << value << std::endl;
    }
}

int main() {
    std::thread prod(producer);
    std::thread cons(consumer);
    prod.join();
    cons.join();
    return 0;
}

This code demonstrates a simple producer-consumer model using condition variables.

What programming languages support condition variables?

Condition variables are supported in many programming languages, including C++, Java, Python, and Go. Each language has its own implementation and syntax.