c++如何使用条件变量（condition_variable）实现同步 _c++条件变量同步方法

// 等待线程
std::thread waiting_thread([&]() {
std::unique_lock<std::mutex> lock(mtx);
cv.wait(lock, []{ return ready; }); // 等待 ready 为 true
// 条件满足，继续执行
std::cout << "继续执行..." << std::endl;
});

std::queue<int> data_queue;
std::mutex mtx;
std::condition_variable cv;
bool finished = false;

void consumer() {
std::unique_lock<std::mutex> lock(mtx);
while (!finished || !data_queue.empty()) {
cv.wait(lock, [&]{ return finished || !data_queue.empty(); });
while (!data_queue.empty()) {
int value = data_queue.front();
data_queue.pop();
std::cout << "消费: " << value << std::endl;
}
}
}

void producer() {
for (int i = 1; i <= 5; ++i) {
{
std::lock_guard<std::mutex> lock(mtx);
data_queue.push(i);
}
cv.notify_one();
std::this_thread::sleep_for(std::chrono::milliseconds(100));
}
{
std::lock_guard<std::mutex> lock(mtx);
finished = true;
}
cv.notify_all();
}

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