C++多线程通信_c++ socket 多线程

#include <iostream>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <future>
#include <csignal>
#include <windows.h>
using namespace std;
std::mutex mlock;
std::condition_variable cv;
bool ready = false;
int thread_entry(int a, char y)
{
std::thread::id  id = std::this_thread::get_id();
cout << "this thread id is " << id << endl;
while (!ready) {
std::this_thread::yield();//交出本线程的时间片使用权，等待下一次调度.可作为一种同步机制。
}
cout << "args:" << a << "\t" << y << endl;
return 0;
}
int thread_entry_uselock(int a, char c)
{	
static int count = 0;
std::thread::id id = std::this_thread::get_id();
cout << "this thread id is " << id << endl;
mlock.lock();
for (int i = 0; i < 300000; ++i)
count++;
cout << "count = " << count << endl;//300000时count出现不是300000倍数的情况，
//说明多线程在访问count的时候有问题了，加锁就OK！
mlock.unlock();
return 0;
}
int thread_entry_uselock_usecv(int a, char c)
{
static int count = 0;
std::thread::id id = std::this_thread::get_id();
cout << "this thread id is " << id << endl;
std::unique_lock<std::mutex> lock(mlock);
while(!ready)
cv.wait(lock);//会先解锁，陷入休眠，让其他竞争此锁mlock的线程得以继续执行；当比唤醒后再上锁
//cv.wait(lock, []() {return ready; });//使用谓词
for (int i = 0; i < 300000; ++i)
count++;
cout << "count = " << count << endl;
return 0;
}
int thread_entry_with_future_promise(std::future<int> *future)
{
std::thread::id id = std::this_thread::get_id();
cout << "this thread id is " << id << endl;
int value = future->get();
cout << "value = " << value << endl;
return 0;
}
int add(int a, int b)
{
return (a + b);
}
int thread_entry_with_future_packaged_task(std::future<int> *future)
{
std::thread::id id = std::this_thread::get_id();
cout << "this thread id is " << id << endl;
int value = future->get();
cout << "value = " << value << endl;
return 0;
}
int main(int argc, char **argv)
{
cout << "****************demo1创建单个线程***************************" << endl;
std::thread th(thread_entry, 1, 'a');//创建线程，并传参
cout << "ready = true" << endl;
ready = true;
if ( th.joinable() )//判断th这个线程是否可连接
th.join();//阻塞连接
else
th.detach();//分离
ready = false;
cout << "****************demo2创建多个线程***************************" << endl;
std::thread thmore[5];
for (int i = 0; i < 5; ++i) {
thmore[i] = std::thread(thread_entry, i, 'b');
}
cout << "ready = true" << endl;
ready = true;
for (int i = 0; i < 5; ++i) {
thmore[i].join();//阻塞连接
}
ready = false;
cout << "****************demo3使用mutex***************************" << endl;
std::thread th_uselock[5];
for (int i = 0; i < 5; ++i) {
th_uselock[i] = std::thread(thread_entry_uselock, i, 'c');
}
cout << "ready = true" << endl;
ready = true;
for (int i = 0; i < 5; ++i) {
th_uselock[i].join();//阻塞连接
}
ready = false;
cout << "****************demo4使用mutex + condition_variable*************" << endl;
std::thread th_uselock_usecv[5];
for (int i = 0; i < 5; ++i) {
th_uselock_usecv[i] = std::thread(thread_entry_uselock_usecv, i, 'd');
}
char c;
cout << "ready?" << endl;
cin >> c;
if ( (c == 'Y') || (c =='y') ) {
ready = true;
//cv.notify_one(); //随机唤醒一个等待的线程
cv.notify_all();   //唤醒cv上等待的所有线程，应避免惊群效应
}
else
cout << "Now is not ready!" << endl;
for (int i = 0; i < 5; ++i) {
th_uselock_usecv[i].join();//阻塞连接
}
ready = false;
cout << "****************demo5使用comm with future-promise*************" << endl;
std::promise<int> promise;
std::future<int> future = promise.get_future();
std::thread thread_future_promise = std::thread(thread_entry_with_future_promise, &future);
promise.set_value(int(2));
thread_future_promise.join();
cout << "****************demo6使用comm with future-packaged_task*************" << endl;
std::packaged_task<int(int, int)> task(add);
std::future<int> future1 = task.get_future();
std::thread thread_future_packaged_task = std::thread(thread_entry_with_future_packaged_task, &future1);
Sleep(3000);//3s
std::thread thread_task(std::move(task), 2, 5);
thread_task.join();
thread_future_packaged_task.join();
cout << "****************demo7使用comm with async*************" << endl;
auto f = std::async(std::launch::async, add, 3, 3);
cout << "async f.get = " << f.get() << endl;
return 0;
}