Re: inhibit compiler warning C4624 for a class hierarchy

"Igor Tandetnik" <itandetnik@mvps.org> wrote in message
news:eWn8hhaOHHA.4928@TK2MSFTNGP06.phx.gbl...


What if it's explicitly declared and never defined (classic trick for
preventing constructors in derived classes)? I just checked, and
__has_trivial_constructor(TOp) is false. If a class does not have a trivial
constructor, does it necessarily have a non-trivial constructor, or can it
have no constructor at all?

  struct PNPEXPORT IConcurrentOperations::OpMessage abstract
  {
   friend void* IConcurrentOperations::alloc_helper(size_t);
  private:
   /**
    ** \brief custom allocator for operational messages
    **
    ** \param[in] bytes number of bytes requested
    ** \return pointer to a block of (at least) size bytes, or NULL if
insufficient memory if available
    **/
   static void* alloc(size_t bytes)
   {
    return malloc(bytes);
   }

  private:
   // prevent creation of objects of subtypes, because
   // virtual destruction is impossible
   OpMessage() throw();
   OpMessage(const OpMessage&) throw();
   void* operator new(size_t) throw();
   void operator delete(void*) throw();

  public:
   size_t reservedbytes() const { return 0; }

  protected:
   /**
    ** \brief custom deallocator for operational messages
    **
    ** \param[in] p pointer to memory block to be freed
    **/
   static void dealloc(void* p)
   {
    free(p);
   }
  };
  inline void* IConcurrentOperations::alloc_helper( size_t bytes )
  {
   return OpMessage::alloc(bytes);
  }