C++11中function对象作回调函数的用法

来源：互联网发布：保护眼睛的电脑软件编辑：程序博客网时间：2024/05/18 08:13

主要参考了这篇博文http://www.cnblogs.com/inevermore/p/4038498.html，感谢原作者。

Thread中的函数回调方法，保存着以后使用。

#ifndef THREAD_H_#define THREAD_H_#include <boost/noncopyable.hpp>#include <functional>#include <pthread.h>class Thread : boost::noncopyable{public:    typedef std::function<void ()> ThreadCallback;    Thread(ThreadCallback callback);    ~Thread();    void start();    void join();    static void *runInThread(void *);private:    pthread_t threadId_;    bool isRunning_;    ThreadCallback callback_; //回调函数};#endif //THREAD_H_

#include "Thread.h"Thread::Thread(ThreadCallback callback): threadId_(0),  isRunning_(false),  callback_(std::move(callback))//move将表达式转换为右值{}Thread::~Thread(){    if(isRunning_)    {        pthread_detach(threadId_);    }}void Thread::start(){    pthread_create(&threadId_, NULL, runInThread, this);    isRunning_ = true;}void Thread::join(){    pthread_join(threadId_, NULL);    isRunning_ = false;}void *Thread::runInThread(void *arg){    Thread *pt = static_cast<Thread*>(arg);    pt->callback_(); //调用回调函数    return NULL;}

(1) 将普通函数作为回调函数

void foo(){    while(1)    {        printf("foo\n");        sleep(1);    }}int main(int argc, char const *argv[]){    Thread t(&foo);    t.start();    t.join();    return 0;}

(2) 类的成员函数作为回调函数

class Foo{public:    void foo(int i)    {        while(1)        {            printf("foo %d\n", i++);            sleep(1);        }    }};int main(int argc, char const *argv[]){    Foo f;    int i = 34;    Thread t(bind(&Foo::foo, &f, i));    t.start();    t.join();    return 0;}

(3) 组合一个新的线程类

class Foo{public:    Foo()    : thread_(bind(&Foo::foo, this))    {    }    void start()    {        thread_.start();        thread_.join();    }    void foo()    {        while(1)        {            printf("foo\n");            sleep(1);        }    }private:    Thread thread_;};int main(int argc, char const *argv[]){    Foo f;    f.start();    return 0;}

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