Struggling with optional funtionality in a derived class

Hello,

To start with I don't know if the way I am skinning this cat is a good way
or not, so if there is a better way of doing it all together please let me
know.

I want to enable functionality (members functions + variables) in a
template
class based on a compile time known flag such that if the flag is false
then
trying to use the functions causes a compile error. What I have tried is
deriving from a base class with a flag which works ok to include/exclude
variable and functionality from the optional bit. However, I can't figure
out how then to get access to the base class functions.

I failed miserably at passing the derived type as a template parameter
because I couldn't figure out how to then make the explicit <T, true>
version of the extra stuff class to work.

e.g.
template<bool enable> class CBit { };
template<> class CBit<true> { ... stuff...  };
template<class T, bool incl> class CBoss : public CBit<incl> {...
stuff...};

This is fine but I don't know how to do it with...
template<class T, bool enable> class CBit { };
template<urm?...

(is this actually a partial specialisation because I read on the internet
that you can't keep a type from the original declaration in the partial
specialisation?)

Is there a way of getting the type sent through as a template argument so
I
can use it?

Is there a way of determining the type of your derived class regardless of
anything else? (The types are all static so you can check an assumed type
with satic_cast but can you find it somehow & make a typedef out of it?)

Source of a test program is below.

Thanks,

Chris

-------------------------------------

#include <stdio.h>
#include <conio.h>

template<bool enable>
class CBit { };

template<>
class CBit<true>
{
public:
  CBit() {k=99;}
  void stuff();

private:
  int get() {return k;}
  int k;
};

template<class T, bool incl>
class CBoss
: private CBit<incl>
{
  typedef CBoss<T,incl> myT;
  friend typename CBit<incl>;

public:
  void foo()
  {
   printf("foo()\n");
   stuff();
   printf("\n\n");
  }

private:
  void bar(int g)
  {
   printf("bar() = %d\n", g);
  }
  int bossstuff;

};


int main(int argc, char *argv[ ])
{
  CBoss<int,false> my;
  CBoss<int,true> myTrue;

  printf("sizeof: my=%d, myTrue=%d\n",sizeof(my),sizeof(myTrue));

  // my.foo();
  myTrue.foo();

  _getch();
  return 0;
}



template<> void CBit<true>::stuff()
{
  printf("stuff, true\n");

  typedef CBoss<int,true> D; // How to get this type at compile time???
//Obviously this only works because I know I have a <int,true> in the
sample!

  D* pDerived;
  pDerived = static_cast<D*>(this);

  pDerived->bar( get() );
}






-- 
      [ See http://www.gotw.ca/resources/clcm.htm
for info about ]
      [ comp.lang.c++.moderated.    First time posters: Do this! ]