C++11多线程入门


线程创建

#include //C++11引入的标准线程库
thread t(TestThreadFun);//thread t= thread
(TestThreadFun);//创建了一个线程对象来执行线程函数TestThreadFun
thread* pt = new thread(TestThreadFunction);//直接创建出来的线程对象,如果没有说明销毁的方式,在程序结束的时候回产生错误。
  • 说明线程销毁方式有两种
  • detach:使线程和主线程之间不再有联系
  • join:如果是join方式,主线程要等join的线程结束才能执行
  • t.detach();

互斥锁

#include//互斥锁对象
mutex g_Mutex1;//创建互斥锁对象
int g_num=0;
lock_guard _selfunlock(g_Mutex1);//自解锁,出了作用域自动销毁
g_Mutex1.lock();//锁住
g_num++;
g_Mutex1.unlock();//解锁
  • 使用互斥锁的时候,虽然能够保证公共数据点安全,但是不能乱用
    锁的数据范围,尽可能的小,锁住的东西越多越慢,锁越多也越慢。

原子变量

#include
 
atomicg_num_ato;//atomic_int g_num_ato;//原子变量
atomic_int//等价上面
//原子操作支持的类型

typedef atomic atomic_bool;

typedef atomic atomic_char;
typedef atomic atomic_schar;
typedef atomic atomic_uchar;
typedef atomic atomic_short;
typedef atomic atomic_ushort;
typedef atomic atomic_int;
typedef atomic atomic_uint;
typedef atomic atomic_long;
typedef atomic atomic_ulong;
typedef atomic atomic_llong;
typedef atomic atomic_ullong;

typedef atomic atomic_char16_t;
typedef atomic atomic_char32_t;

typedef atomic atomic_wchar_t;

typedef atomic atomic_int8_t;
typedef atomic atomic_uint8_t;
typedef atomic atomic_int16_t;
typedef atomic atomic_uint16_t;
typedef atomic atomic_int32_t;
typedef atomic atomic_uint32_t;
typedef atomic atomic_int64_t;
typedef atomic atomic_uint64_t;

typedef atomic atomic_int_least8_t;
typedef atomic atomic_uint_least8_t;
typedef atomic atomic_int_least16_t;
typedef atomic atomic_uint_least16_t;
typedef atomic atomic_int_least32_t;
typedef atomic atomic_uint_least32_t;
typedef atomic atomic_int_least64_t;
typedef atomic atomic_uint_least64_t;

typedef atomic atomic_int_fast8_t;
typedef atomic atomic_uint_fast8_t;
typedef atomic atomic_int_fast16_t;
typedef atomic atomic_uint_fast16_t;
typedef atomic atomic_int_fast32_t;
typedef atomic atomic_uint_fast32_t;
typedef atomic atomic_int_fast64_t;
typedef atomic atomic_uint_fast64_t;

typedef atomic atomic_intptr_t;
typedef atomic atomic_uintptr_t;
typedef atomic atomic_size_t;
typedef atomic atomic_ptrdiff_t;
typedef atomic atomic_intmax_t;
typedef atomic atomic_uintmax_t;

多线程进度条练习

  • 用线程调用加载资源的函数(每次循环随机等待一下,没循环一次修改一下全局的进度变量)
    主线程中,循环访问全局进度变量,将当前的进度换成百分比输出,并且绘制进度条的变化
  • printf("当前线程的id: %d\n", this_thread::get_id());//获取线程id
  • this_thread::sleep_for(std::chrono::seconds(rand()%5+1));//#include 或者引入头文件
#include
#include
#include
#include
using namespace std;

atomicg_num_ato=0;

void fun(int n)
{
	for (int i = 0; i < n; i++)
	{
		g_num_ato++;
		this_thread::sleep_for(std::chrono::seconds(rand()%5+1));
	}
}
int main()
{
	thread t = thread(fun,100);
	t.detach();
	
	while (g_num_ato <100)
	{
		system("cls");
		int iTemp = g_num_ato;
		cout << "当前值是:" << iTemp << "%" << endl;
		for (int i = 0; i < iTemp /5; i++)
		{
			cout << "★";
		}
	}
	cout << "加载完成"<