C++ Boost signal2信号/插槽知识点

signals2基于Boost的另一个库signals，实现了线程安全的观察者模式。在signals2中，观察者模式被称为信号/插槽（signals and slots），它是一种函数回调机制，一个信号关联了多个插槽，当信号发出时，所有关联它的插槽都会被调用。

下面就通过小案列来实现signal的使用

#include 
#include 
#include 
#include 

using namespace std;


class Button{

private:
	typedef boost::signals2::signal signalDef;
	typedef boost::signals2::signal::slot_type slotType;

private:
	signalDef mysignal;
	boost::signals2::connection mConnection;


public:
	boost::signals2::connection connectFun(const slotType& type){
		mConnection = mysignal.connect(type);
		return mConnection;
	}

	void sendSignal(){
		mysignal(10,20);
	}

};

void fun1(int a, int b){
	cout << "add result :" << a + b << endl;
}

void fun2(int a, int b){
	cout << "sub result :" << a - b << endl;
}

void fun3(int a ,int b){
	cout << "multi result :" << a * b << endl;
}


void main(){

	Button button;
	boost::signals2::connection con1 = button.connectFun(fun1);
	boost::signals2::connection con2 = button.connectFun(fun2);
	boost::signals2::connection con3 = button.connectFun(fun3);
	//con3.disconnect();
	while(1){

		system("pause");
		button.sendSignal();
	
	}


     cin.get();
}

下面槽函数是类的成员函数的时候

#include 
#include 
#include 
#include 

using namespace std;
using namespace boost;

template 
class Signal{

public:
	//typedef 信号
	typedef boost::signals2::signal defSignal;
    typedef typename defSignal::slot_type defSlot;

public:
	//连接槽函数
	boost::signals2::connection connectFun(const defSlot& slot);

	//重载伪函数
	void operator()(typename defSignal::template arg<0>::type a0,typename defSignal::template arg<1>::type a1);

private:
	defSignal mSignal;


};

//接收信号后响应的函数
class FunRecv1{

public:
	void action(int a, int b){
	  cout << "add result" << a + b << endl;
	}

};

//接收信号后响应的函数
class FunRecv2{

public:
	void action(int a, int b){
	  cout << "multi result" << a * b << endl;
	}

};
 
//实现
template 
boost::signals2::connection  Signal::connectFun(const defSlot& slot){
	return mSignal.connect(slot);
}

template 
void Signal::operator()(typename defSignal::template arg<0>::type a0,typename defSignal::template arg<1>::type a1){
	mSignal(a0,a1);
}
void main(){
    
	Signal mysignal;
	FunRecv1 fun1;
	FunRecv2 fun2;

	//boost::function myfun = boost::bind(&FunRecv1::action,&fun1,_1,_2);
	//信号连接槽函数
	boost::signals2::connection con1 = mysignal.connectFun(boost::bind(&FunRecv1::action,&fun1,100,200));
	boost::signals2::connection con2 = mysignal.connectFun(boost::bind(&FunRecv2::action,&fun2,11,22));
	mysignal(100,200);

	con2.disconnect();
	mysignal(100,200);

    cin.get();
}

到这就能明白signal信号机制的重要性 观察者与被观察者的模式

参考博客：http://www.tuicool.com/articles/ZvYNze