implement template class like std::tr1::function

[aj3423]

Hi,
I'm trying to implement a simple signal class, here's the code:

//R=return value, T1=arg type1, T2=arg type2
template<typename R, typename T1, typename T2>
struct sig {...}

and I see the std::tr1::function looks like:

tr1::function<R(T1,T2)> fn;

<R(T1,T2)> makes more sense than <R,T1,T2>, but how to implement this?
I tried to look into the source <functional> but failed to understand that.

Thanks in advance.

[viliml]

First it makes an empty general template definition

  template<typename _Signature>
    class function;

Then, it specializes it for functions

  template<typename _Res, typename... _ArgTypes>
    class function<_Res(_ArgTypes...)>

You can do this:

template<typename T>
struct sig;//empty for a reason

template<typename R, typename T1, typename T2>
struct sig<R(T1, T2)>
{
//implement it here
};

[aj3423]

That's it. Thanks viliml.