Re: partial specialized templated classes

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 24 Jul 2007 14:34:14 -0400
Message-ID:
<f85gn4$4ej$1@news.datemas.de>
Olaf wrote:

[..] I have the following
classes:

   template<typename T, long CURLOPT_ID>
   class CurlOption: boost::noncopyable {
   public:
       typedef typename boost::call_traits<T>::param_type param_type;
       ....
   public:
       // constructors:
       CurlOption() {}
       CurlOption(param_type v) : m_value(v) {}

   public:
       long option() const { return CURLOPT_ID; }
       result_type parameter() { return m_value; }
       void setopt(CURL* handle);

   private:
       value_type m_value;
   };

and the specialized for the templated arguments T (ether bool, long,
std::string etc.):

   template<long CURLOPT_ID>
   class CurlOption<bool, CURLOPT_ID> {
   public:
       void setopt(CURL* handle) {
           curl_easy_setopt(handle,
                            this->option(), this->value() ? 1 : 0);
       }
   };

e.g. used like

[.. some errors, with the message in German, I can't read German ..]

Obviously the right ctor is missing. Anyway, do I have all the stuff
from the Template (typedefs including) to rewrite for the specialized
template class?


Of course.

Or is there another way?


Not really.

I thought I need only to
overwrite the specialized members - where is my mistake?


Your mistake in thinking that a template specialisation contains all
stuff from the unspecialised one except the stuff you [re]define. It
does not.

Is there a
better and correct way?


Inheritance, maybe? You still can't inherit constructors, though.

V
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