Force type of C++ template

Question

I\'ve a basic template class, but I\'d like to restrain the type of the specialisation to a set of classes or types. e.g.:

template 
class          


        

Answer 1

Yust a quick idea, I'm sure there are better approaches:

template  struct protector {
static const int result = 1;
};

template <> struct protector {
static const int result = -1;
};

template  
class MyClass
{
   private:
     char isfine[protector::result];
};

It might be better, however, to put a fat comment over your code to keep users from instantiating with the wrong types :-)