Boost::Function 是对函数指针的对象化封装，在概念上与广义上的回调函数类似。相对于函数指针，function除了使用自由函数，还可以使用函数对象，甚至是类的成员函数，这个就很强大了哈

#include <boost/function.hpp>
#include <boost/bind.hpp>
#include <iostream>using namespace std;class TestA
{public:void method(){cout<<"TestA: method: no arguments"<<endl;}void method(int a, int b){cout<<"TestA: method: with arguments"<<"value of a is:"<<a <<"value of b is "<<b <<endl;}
};void sum(int a, int b)
{int sum = a + b;cout<<"sum: "<<sum<<endl;
} int main()
{boost::function<void()> f;TestA test;f = boost::bind(&TestA::method, &test);f();f = boost::bind(&TestA::method, &test, 1, 2);f();f = boost::bind(&sum, 1, 2);f();
}

2. 应用：Thread封装

在实现自定义的线程类时，曾经这么干过：定义虚函数run()，用户自定义的CustomThread::Thread后，自己实现run()函数就OK了。 当时觉得这么做也不错。
现在有了boost::function/boost::bind我们可以这么干：
定义一个线程类：
.h文件

#include <pthread.h>
#include <string>
#include <boost/function.hpp>
#include <boost/bind.hpp>using namespace std;
class Thread
{typedef boost::function<void()> ThreadFun;public:Thread(const ThreadFun& threadFun,const string& threadName = string());pid_t     getThreadId();string    getThreadName();int       start();private:static void* startThread(void* thread);private:pthread_t   m_thread; //线程句柄pid_t       m_tid;    //线程IDstring      m_strThreadName;    //线程名称bool        m_bStarted;         //线程是否启动ThreadFun   m_func;             //线程处理函数
};

.cpp

#include "thread.h"Thread::Thread(const Thread::ThreadFun& threadFun, const string& threadName):
m_func(threadFun), m_strThreadName(threadName)
{
}int Thread::start()
{m_tid = pthread_create(&m_thread, NULL, &startThread, this);return 0;
}void* Thread::startThread(void* obj)
{Thread* thread = static_cast<Thread*>(obj);thread->m_func();return NULL;
}pid_t Thread::getThreadId()
{return m_tid;
};string  Thread::getThreadName()
{return m_strThreadName;
}

void ThreadProcess()
{int count = 100;for (int i = 0; i < count; i++){if (i % 10 == 0)    cout<<"\n";cout<<i<<"\t";}
}int main()
{boost::function<void()> f;f = boost::bind(&ThreadProcess);    Thread thread(f, "ThreadTest");thread.start();sleep(1000*1000);return 0;
}