Herb Sutter's Example:CallBack,But there is a problem if i need a param

[Rester]

//the simple code

template<typename T>
class CallBack
{
public:
typedef void (T::*Func)(unsigned short);
    CallBack(T *t, Func f):_t(t),_f(f)
    {}
    void operator()(unsigned short port)
    {
         _t->*_f(port);
    }
private:
    T *_t;
    Func _f;
}
//test base class
class testBase
{
public:
virtual ~testBase(){};
virtual void do(unsigned short port) = 0;
};
//test class
class Test: public testBase
{
public:
void do(unsigned short port)
{...}
};
//
// std::list<unsigned short> someList;
// std::list<Test*>::iterator it ...
//
for_each(someList.begin(),someList.end(),CallBack<testBase>(*it,&testBase::do));
// has an error 
// C2064: term does not evaluate to a function taking 1 arguments with VS2005
 

does anyone know how to do this? thanks!

[JosAH]

You cannot name a function 'do', i.e. it's a reserved word.

kind regards,

Jos

[Rester]

You cannot name a function 'do', i.e. it's a reserved word.

kind regards,

Jos

sorry just a mistake, I mean just a Function Name here's code:

template<typename T>
class CallBack
{
public:
typedef void (T::*Func)(unsigned short);
    CallBack(T *t, Func f):_t(t),_f(f)
    {}
    void operator()(unsigned short port)
    {
         _t->*_f(port);
    }
private:
    T *_t;
    Func _f;
}
//test base class
class testBase
{
public:
virtual ~testBase(){};
virtual void doSomething(unsigned short port) = 0;
};
//test class
class Test: public testBase
{
public:
void doSomething(unsigned short port)
{...}
};
//
// std::list<unsigned short> someList;
// std::list<Test*>::iterator it ...
//
for_each(someList.begin(),someList.end(),CallBack<testBase>(*it,&testBase::doSomething));
// has an error 
// C2064: term does not evaluate to a function taking 1 arguments with VS2005
 

how to do it ? thanks

[JosAH]

sorry just a mistake, I mean just a Function Name here's code:

template<typename T>
class CallBack
{
public:
typedef void (T::*Func)(unsigned short);
    CallBack(T *t, Func f):_t(t),_f(f)
    {}
    void operator()(unsigned short port)
    {
         _t->*_f(port);
    }
private:
    T *_t;
    Func _f;
}
//test base class
class testBase
{
public:
virtual ~testBase(){};
virtual void doSomething(unsigned short port) = 0;
};
//test class
class Test: public testBase
{
public:
void doSomething(unsigned short port)
{...}
};
//
// std::list<unsigned short> someList;
// std::list<Test*>::iterator it ...
//
for_each(someList.begin(),someList.end(),CallBack<testBase>(*it,&testBase::doSomething));
// has an error 
// C2064: term does not evaluate to a function taking 1 arguments with VS2005
 

how to do it ? thanks

The first parameter of your CallBack constructor call isn't correct; change the
for_each line to two lines:

TestBase tb;
for_each(someList.begin(),someList.end(),CallBack<testBase>(&tb ,&testBase::doSomething));

kind regards,

Jos

[Rester]

The first parameter of your CallBack constructor call isn't correct; change the
for_each line to two lines:

TestBase tb;
for_each(someList.begin(),someList.end(),CallBack<testBase>(&tb ,&testBase::doSomething));

kind regards,

Jos

(*it) means a pointer to a Test*

such as:

std::list<testBase*> testList;
testList.push_back(new Test());
std::list<unsigned short>::iterator it = testList.begin();
//that should be correct,OK?
for_each(someList.begin(),someList.end(),CallBack<testBase>((*it) ,&testBase::doSomething))
 

Thanks

[JosAH]

(*it) means a pointer to a Test*

such as:

std::list<testBase*> testList;
testList.push_back(new Test());
std::list<unsigned short>::iterator it = testList.begin();
//that should be correct,OK?
for_each(someList.begin(),someList.end(),CallBack<testBase>((*it) ,&testBase::doSomething))
 

Thanks

No, now your iterator 'it' is an iterator over a list of unsigned shorts. I played a
bit with your code (and changed some names on the fly). This is what I got
(it works):

// in my .h file:
template<class T>
class CallBack
{
public:
    typedef void (T::*func_t)(int);
 
    CallBack(T* t, func_t f):_t(t),_f(f) {}
    void operator()(int p) {
         (_t->*_f)(p);
    }
 
private:
    T*_t;
    func_t _f;
};
 
class DoFunc {
public:
       virtual void func(int i) { std::cout << i << std::endl; }
};

I tested that bit with this:

// in my .cpp file:
    vector<int> v;
 
    for (int j= 0; j < 10; j++)
        v.push_back(j);
 
    vector<DoFunc*> df;
 
    df.push_back(new DoFunc());        
    vector<DoFunc*>::iterator it= df.begin();
 
    for_each(v.begin(),v.end(),CallBack<DoFunc>(*it, &DoFunc::func));

kind regards,

Jos

[Rester]

god save me , how many mistake i have made;
in fact all i want to write is std::list<testBase*>::iterator it = testList.begin(),
but I …
sorry for my baby mistakes;
(_t->*_f)(p); //-----------------------I missed the brackets
Now it works fine , Thank you very much ,Jos.

[JosAH]

(_t->*_f)(p); //-----------------------I missed the brackets
Now it works fine , Thank you very much ,Jos.

Oh dear, I missed it completely that your code didn't have the parentheses;
I just assumed you typed the same stuff as I did when I tested your idea ...
Well, we solved the problem by sheer serendipity then ;-)

kind regards,

Jos