Re: How to get rid of the new-initializer in a new-expression

Carl Barron <>
Tue, 19 Feb 2008 01:08:27 CST
In article <>, Matthias Hofmann
<> wrote:

"Alberto Ganesh Barbati" <> schrieb im Newsbeitrag

Why don't you simply define your new as:

  #define NEW(T) TrackNew(new T)

and let the compiler deduce the type of the argument?

My example was a little simplified. In my original code, TrackNew() looks
more like this:

template <class T>
struct TrackNewImpl
     static T* TrackNew( MemoryTracker& inst,
         T* ptr, const char* file, int line )
         // Do memory tracking for objects.

         return ptr;

template <class T, std::size_t N>
struct TrackNewImpl<T[N]>
     static T* TrackNew( MemoryTracker& inst,
         T* ptr, const char* file, int line )
         // Do memory tracking for arrays.

         return ptr;

template <class T> typename extract<T>::type*
     TrackNew( typename extract<T>::type* ptr,
     const char* file, int line )
     return TrackNewImpl<T>::TrackNew( *this,
         ptr, file, line );

   Seems like the best place to track the proper deletion operation is in
a smart ptr. Shared_ptr and boost::intrusive_ptr can do this, if you
can modify each T. Shared_ptr is probably the choice if there are lots
of T's.

If your allocation returns a shared_ptr of a private access nested
deleter so the user has no direct access to it or the type for safety
the delete can choose the proper deleter when the shared_ptr says
its time to delete the ptr.

Exposition only not tested headers / using clauses missing for

template <class T>
class TrackerManagerObject
       struct deleter
          bool array;
          deleter(bool a):array(a){}
          void operator() (T *p)
             if(array) delete [] p;
             else delete p;
       shared_ptr<T> ptr;
    explicit TrackerManagementObject(T *p,bool a = false)

    // allow user to create a shared_ptr<T> easily
    operator shared_ptr<T>() const {return ptr;}

    // determine if this is array ...
    bool is_array() const
       deleter *p = get_deleter<deleter>(ptr);
       assert(p); // probably not needed
       return p->array;
    // ,,,

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