local variable as non-type argument

[mirkuh]

Hi,

instead of writing this

SomeFunction<Class>::Bind<&Class::MemberFunction>(this);

I want to provide an easier way to call "SomeFunction".

I have one solution using a macro like this:

GET_EXAMPLE(Class, &Class::MemberFunction, this);
//...
#define GET_EXAMPLE(ClassName, MemberFunctionPointer, InstancePointer) \
  (SomeFunction<ClassName>::Bind<MemberFunctionPointer>(InstancePointer))

But in order to avoid the use of this macro I'd like to do something like the following. The problem is that I get the error: template parameter 'T_MEMBER_FUNCTION' : 'MemberFunctionPointer' : a local variable cannot be used as a non-type argument

//...
GetExample(&Class::MemberFunction, this));
//...
template<class T_CLASS>
inline static void GetExample(void (T_CLASS::*MemberFunctionPointer)(), T_CLASS* InstancePointer)
{
  SomeFunction<T_CLASS>::Bind<MemberFunctionPointer>(InstancePointer);
}

Any solutions to this problem?

Thanks,
Mirco

[alwaysLearning0]

Hi,

Why you want to bind member function type with a static bind method? you wont be able to call it without having proper address of class member function.

Anyway, I hope following code helps, let me know if it works?

#include <iostream>
using namespace std;


template <typename T>
class SomeFunction{
        T instance;
public:
        template <typename FunPtr>
        void Bind(T _instance, FunPtr funPtr){
                //Bind your funPtr here.
                //use a place holder to hold the FunPtr type as you will want to use it
        }
};

template <typename T, typename FunPtr> //Let argument deduction find out the type.
void Function(T instance, FunPtr funPtr){
        (instance.*funPtr)();
}

class AClass{
public:
        void ClassFun(){
                cout << "Class is having fun" << endl;
        }
};

int main() {

        AClass x;
        Function(x,&AClass::ClassFun);

        return 0;
}

Can yo explain what exactly your bind method will do and what you want to do after binding the type? then may be i could give more proper example.

[mirkuh]

Hi,

the Bind-method calls the constructor of a class CDelegate which instantiates objects that store a function pointer and an object pointer. I use this mechanism to register ISRs in an embedded system.
Everything works fine, I just want to provide an easier way to call the Bind-method in form of avoiding the use of <>.

What I want is passing a function pointer as paramater to a wrapper function. In this wrapper function I want to use this function pointer as a non-type template parameter and pass it to the Bind-method. As I figured out it is not possible to first pass it as a standard function parameter and then use it as a template parameter because in this case it will not be known to the compiler at compile time...

[alwaysLearning0]

Yea, you are right, you wont get the address of the function compile time.

I just want to provide an easier way to call the Bind-method in form of avoiding the use of <>.

Doesn't argument deduction shown on my last post help?

[mirkuh]

In your post in Function() you call ClassFun() directly but I need the function pointer in Function() to again pass it as a non-type template parameter. I can't do this with local variables I guess.