template class

[aayu09]

I am working on a software project and I don't understand the following c++ function:

template<class T>
user_type_t foo(T* object, user_type_t(T::*method)(event*))
{
    T::ATTEMPING_TO_DO_SOMETHING();
    return goo(object, (user_method_t)method);
}

user_type_t goo(user_object_t object, user_method_t method)
{
    //so something
    return S_TRANSITION;
}

I don't know what T::*method mean here, please help.

Thanks in advance,

aayu09

[stravant]

It's a member function pointer, in this case a pointer to a method of the class "T" that takes a pointer to an event and returns a user_type_t. Search "pointer to member function" for more info on it, their syntax and semantics are fairly complicated.

[PiMaster]

http://www.cplusplus.com/doc/tutorial/templates/
Basically, a template allows you to create a class or function with generic types. In this example, T is replaced with whatever you place in between the <>'s:

foo<myType>(myObject,myFunction);

This lets you use any type for myObject.

[aayu09]

Thanks a lot, I got it.

[jsmith]

BTW, this line: return goo(object, (user_method_t)method);

almost certainly does not work in all cases if the explicit cast is necessary.