79 lines
2.0 KiB
C++
79 lines
2.0 KiB
C++
//
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// Created by light on 19-11-5.
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//
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#include <iostream>
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#include <thread>
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#include <unistd.h>
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#include <vector>
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#include <algorithm>
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#include <functional>
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using namespace std;
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void some_function() {}
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void some_other_function() {}
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// std::thread不支持拷贝语义。
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// std::thread支持移动语义。
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// scoped_thread实例
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void do_something(int i) {
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cout << i << endl;
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}
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struct func {
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int &i;
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func(int &i_) : i(i_) {}
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void operator()() {
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for (unsigned j = 0; j < 1000000; ++j) {
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do_something(i);
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}
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}
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};
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class scoped_thread {
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std::thread t;
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public:
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explicit scoped_thread(std::thread t_) : // 1
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t(std::move(t_)) {
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if (!t.joinable()) // 2
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throw std::logic_error("No thread");
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}
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~scoped_thread() {
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t.join(); // 3
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}
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scoped_thread(scoped_thread const &) = delete;
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scoped_thread &operator=(scoped_thread const &) = delete;
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};
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void do_work(unsigned id) {}
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void f() {
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std::vector<std::thread> threads;
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for (unsigned i = 0; i < 20; ++i) {
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threads.push_back(std::thread(do_work, i)); // 产生线程
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}
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std::for_each(threads.begin(), threads.end(),
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std::mem_fn(&std::thread::join)); // 对每个线程调用join()
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}
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int main() {
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// std::thread t1(some_function); // 构造一个thread对象t1
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// std::thread t2 = std::move(t1); // 把t1 move给另外一个thread对象t2，t1不再管理之前的线程了。
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// // 这句不需要std::move()，从临时变量进行移动是自动和隐式的。调用的是operator=(std::thread&&)
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// t1 = std::thread(some_other_function);
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// std::thread t3;
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// t3 = std::move(t2); // 把t2 move给t3
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// // 把t3 move给t1，非法。因为`t1`已经有了一个相关的线程，会调用`std::terminate()`来终止程序。
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// t1 = std::move(t3);
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f();
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return 0;
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} |