原文地址：https://www.cnblogs.com/lzpong/p/6397997.html[C++] 纯文本查看 复制代码 #include <iostream>
#include <vector>
#include <queue>
#include <atomic>
#include <future>
#include <condition_variable>
#include <thread>
#include <functional>
#include <stdexcept>
namespace wind
{
#define THREADPOOL_MAX_NUM 16
class threadpool
{
using Task = std::function<void()>; //定义类型
std::vector<std::thread> m_pool; //线程池
std::queue<Task> m_tasks; //任务队列
std::mutex _lock; //同步
std::condition_variable m_cv_task; //条件阻塞
std::atomic<bool> m_run; //线程池是否执行
std::atomic<int> m_idle_num; //空闲线程数量
public:
inline threadpool(size_t size = 4)
{
this->m_run = true;
this->m_idle_num = 0;
addThread(size);
}
inline ~threadpool()
{
m_run = false;
m_cv_task.notify_all();
for (auto &thread : this->m_pool)
{
if(thread.joinable())
thread.join();
}
}
public:
template<class F, class... Args>
auto commit(F&& f, Args&&... args) ->std::future<decltype(f(args...))>
{
if (!m_run)
throw std::runtime_error("commit on ThreadPool is stopped.");
// 萃取类型 得到函数返回类型
using RetType = decltype(f(args...));
// 智能指针
auto task = std::make_shared<std::packaged_task<RetType()>>(
std::bind(std::forward<F>(f), std::forward<Args>(args)...)
);
std::future<RetType> future = task->get_future();
// 插入一个任务
{
std::lock_guard<std::mutex> lock{ _lock };
m_tasks.emplace(
[task]
{
(*task)();
});
}
// 通知任意一个线程 当前有任务到来
m_cv_task.notify_one();
return future;
}
//空闲线程数量
int idlCount() { return m_idle_num; }
//线程数量
int thrCount() { return m_pool.size(); }
private:
//添加指定数量的线程
void addThread(size_t size)
{
// 创建size个线程
for (int i = 0; i < size; i++)
{
m_pool.emplace_back(
[this]
{
while (m_run)
{
Task task;
{
std::unique_lock<std::mutex> lock{ _lock };
// 等待任务队列有任务到来
m_cv_task.wait(lock, [this]{
return !this->m_run || !this->m_tasks.empty();
});
if (!m_run && m_tasks.empty())
return;
// 按先进先出从队列取一个 task
task = std::move(m_tasks.front());
m_tasks.pop();
}
//执行任务
m_idle_num--;
task();
m_idle_num++;
}
});
m_idle_num++;
}
}
};
}
void fun1(int slp)
{
printf(" hello, fun1 ! %d\n" ,std::this_thread::get_id());
if (slp>0)
{
printf(" ======= fun1 sleep %d ========= %d\n",slp, std::this_thread::get_id());
std::this_thread::sleep_for(std::chrono::milliseconds(slp));
}
}
struct gfun {
int operator()(int n) {
printf("%d hello, gfun ! %d\n" ,n, std::this_thread::get_id() );
return 42;
}
};
class A {
public:
static int Afun(int n = 0) { //函数必须是 static 的才能直接使用线程池
std::cout << n << " hello, Afun ! " << std::this_thread::get_id() << std::endl;
return n;
}
static std::string Bfun(int n, std::string str, char c) {
std::cout << n << " hello, Bfun ! "<< str.c_str() <<" " << (int)c <<" " << std::this_thread::get_id() << std::endl;
return str;
}
};
int main()
{
try {
wind::threadpool executor{16};
A a;
std::future<void> ff = executor.commit(fun1,0);
std::future<int> fg = executor.commit(gfun{},0);
std::future<int> gg = executor.commit(a.Afun, 9999); //IDE提示错误,但可以编译运行
std::future<std::string> gh = executor.commit(A::Bfun, 9998,"mult args", 123);
std::future<std::string> fh = executor.commit([]()->std::string { std::cout << "hello, fh ! " << std::this_thread::get_id() << std::endl; return "hello,fh ret !"; });
std::cout << " ======= sleep ========= " << std::this_thread::get_id() << std::endl;
std::this_thread::sleep_for(std::chrono::microseconds(900));
for (int i = 0; i < 5; i++) {
executor.commit(fun1,i*100 );
}
std::cout << " ======= commit all ========= " << std::this_thread::get_id()<< " idlsize="<<executor.idlCount() << std::endl;
std::cout << " ======= sleep ========= " << std::this_thread::get_id() << std::endl;
std::this_thread::sleep_for(std::chrono::seconds(3));
ff.get(); //调用.get()获取返回值会等待线程执行完,获取返回值
std::cout << fg.get() << " " << fh.get().c_str()<< " " << std::this_thread::get_id() << std::endl;
std::cout << " ======= sleep ========= " << std::this_thread::get_id() << std::endl;
std::this_thread::sleep_for(std::chrono::seconds(3));
std::cout << " ======= fun1,55 ========= " << std::this_thread::get_id() << std::endl;
executor.commit(fun1,55).get(); //调用.get()获取返回值会等待线程执行完
std::cout << "end... " << std::this_thread::get_id() << std::endl;
wind::threadpool pool(4);
std::vector< std::future<int> > results;
for (int i = 0; i < 16; ++i) {
results.emplace_back(
pool.commit([i] {
std::cout << "hello " << i << std::endl;
std::this_thread::sleep_for(std::chrono::seconds(1));
std::cout << "world " << i << std::endl;
return i*i;
})
);
}
std::cout << " ======= commit all2 ========= " << std::this_thread::get_id() << std::endl;
for (auto && result : results)
std::cout << result.get() << ' ';
std::cout << std::endl;
return 0;
}
catch (std::exception& e) {
std::cout << "some unhappy happened... " << std::this_thread::get_id() << e.what() << std::endl;
}
return 0;
}
c++11 第一次见 看了两天才搞懂 头皮发麻 c++小白可以看下 晕的先大致看一下下面 突然感觉好陌生
[C++] 纯文本查看 复制代码 #include <iostream>
#include <thread>
#include <atomic>
#include <condition_variable>
#include <vector>
#include <functional>
std::atomic<bool> g_var(false);
std::mutex mtx;
std::condition_variable con;
void fun1()
{
std::unique_lock<std::mutex> mm(mtx);
con.wait(mm,
[]
{
return g_var == true;
});
printf("fun1 条件变量成立\n");
// 执行下面结果
}
void fun2()
{
std::unique_lock<std::mutex> mm(mtx);
con.wait(mm,
[]
{
return g_var == false;
});
printf("fun2 条件变量成立\n");
// 执行下面结果
}
void fun3()
{
std::unique_lock<std::mutex> mm(mtx);
con.wait(mm,
[]
{
return g_var == true;
});
printf("fun3 条件变量成立\n");
// 执行下面结果
}
int main(void)
{
std::vector<std::thread> vec;
vec.emplace_back(fun1);
vec.emplace_back(fun2);
vec.emplace_back(fun3);
for (auto &e : vec)
{
if (e.joinable())
e.join();
}
return 0;
} | 
发表于 2020-11-26 17:50
