C++11线程指南(五)--线程的移动语义实现
时间:2014-08-09 11:36:27
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1. 线程的移动语义实现
基于前面几章介绍的移动语义,我们用它来实现线程。#include <iostream>
#include <thread>
#include <vector>
#include <algorithm>
#include <cassert>
int main()
{
std::vector<std::thread> workers;
for (int i = 0; i < 5; i++) {
auto t = std::thread([i]()
{
std::cout << "thread function: " << i << "\n";
});
workers.push_back(std::move(t));
}
std::cout << "main thread\n";
std::for_each(workers.begin(), workers.end(), [](std::thread &t)
{
assert(t.joinable());
t.join();
});
return 0;
} 运行结果为:thread function: thread function: thread function: 01
thread function: 3
2
main thread
thread function: 4
接下来对代码进行一些改变。将线程函数task()独立出来。
#include <iostream>
#include <thread>
#include <vector>
#include <algorithm>
#include <cassert>
void task(int i)
{
std::cout<<"worker : "<<i<<std::endl;
}
int main()
{
std::vector<std::thread> workers;
for (int i = 0; i < 5; i++) {
auto t = std::thread(&task, i);
workers.push_back(std::move(t));
}
std::cout << "main thread" << std::endl;
std::for_each(workers.begin(), workers.end(), [](std::thread &t)
{
assert(t.joinable());
t.join();
});
return 0;
} 运行结果为:worker : worker : 02
worker : 3
worker : 1
main thread
worker : 4
2. 通过引用传递线程参数
下面将线程函数的参数改为引用void task(int &i)
{
std::cout << "worker : " << i << "\n";
} 与此同时,线程的构造函数同样需要相应的修改auto t = std::thread(&task, std::ref(i));
但是,上面程序看似可以工作,不过不是一个好的设计,因为多个线程在同时使用一个指向相同对象的引用。
C++11线程指南(五)--线程的移动语义实现,布布扣,bubuko.com
原文:http://blog.csdn.net/shltsh/article/details/38454273
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