How can I synchronize threads in C++?

How can I synchronize threads in C++?

You can use mutexes to protect shared data and condition variables to manage thread communication.

Can you give me an example of using a mutex?

Sure! Here's a simple example:

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

std::mutex mtx;
int shared_data = 0;

void increment() {
    mtx.lock();
    ++shared_data;
    mtx.unlock();
}

int main() {
    std::thread t1(increment);
    std::thread t2(increment);
    t1.join();
    t2.join();
    std::cout << "Shared data: " << shared_data << std::endl;
}

What are condition variables and how do they work?

Condition variables allow threads to wait for certain conditions to be met. They are used in conjunction with mutexes to avoid busy waiting.

Can you show me a code example using condition variables?

Absolutely! Here's a simple example:

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

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

void wait_for_signal() {
    std::unique_lock<std::mutex> lock(mtx);
    cv.wait(lock, [] { return ready; });
    std::cout << "Thread proceeding after signal!" << std::endl;
}

void send_signal() {
    std::this_thread::sleep_for(std::chrono::seconds(1));
    std::lock_guard<std::mutex> lock(mtx);
    ready = true;
    cv.notify_one();
}

int main() {
    std::thread waiter(wait_for_signal);
    std::thread signaler(send_signal);
    waiter.join();
    signaler.join();
}