[C++知识库]万行代码计划 day03 C++多线程等待

万行代码计划
Day03，100行
进度200/10000

/*20210728
std::unique_lockstd::mutex lock(mutex);// 配合使用std::condition_variable::wait
cv.wait(lock,[]{return quit||!globalList.empty();});//加入等待条件
pool.emplace_back(worker,i);//右值引用，直接构造
cout线程不安全的，printf线程安全的
线程池
线程死循环等待写法避免，占用CPU过高，如何避免？
隔断时间看一下？
线程进入和退出的条件如何处理？
线程等待条件如何设置？
*/

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include<condition_variable>

class Message{
public:
const std::string& data() const{ return m_data;}
Message(std::string d = std::string()):m_data(std::move(d)){}
private:
std::string m_data;
};

std::atomic toatalSize{0};
std::mutex mutex;
std::condition_variable cv;
std::atomic ready{false};
bool quit{false};
std::list globalList;

void worker(int i){
while (!ready){
}
Message msg;
while (!quit)
{
{
std::unique_lockstd::mutex lock(mutex);// 配合使用std::condition_variable::wait
cv.wait(lock,[]{return quit||!globalList.empty();});//加入等待条件
if (quit)
{
return;
}
auto iter = globalList.begin();
msg = std::move(*iter);
globalList.erase(iter);
}
toatalSize += strlen(msg.data().c_str());
}
}

int main()
{
const auto threadCount = 4;
for (size_t i = 0; i < 500000; i++)
{
/* code /
globalList.push_back(“this is a test”+std::to_string(i));
}
std::vectorstd::thread pool;
for (size_t i = 0; i < threadCount; i++)
{
pool.emplace_back(worker,i);//右值引用，直接构造
}
auto beginc = clock();
ready = true;
for (size_t i = 0; i < 300000; i++)
{
/ code /
{
std::lock_guardstd::mutex lock(mutex);
globalList.push_back(std::string(“second”));
}
cv.notify_one();
}
while (true)
{
/ code /
std::lock_guardstd::mutex lock(mutex);
if (globalList.empty())
{
/ code */
quit = true;
cv.notify_all();
break;
}
}

for (auto &v:pool)
{
    /* code */
    if (v.joinable())
    {
        /* code */
        v.join();
    }
}
auto endc = clock();
std::cout<<"total size is "<<toatalSize<<" using time " << endc-beginc<<std::endl;

}