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

From:
Alberto Ganesh Barbati <AlbertoBarbati@libero.it>
Newsgroups:
comp.lang.c++.moderated
Date:
Sun, 17 Feb 2008 21:21:44 CST
Message-ID:
<g2Ztj.248009$%k.378883@twister2.libero.it>
Matthias Hofmann ha scritto:

Hello everyone!

I have written a memory tracker using macros, and everything works fine
unless the new-expression contains a new-initializer. Please take a look at
the following example:

template <class T> T* TrackNew( T* ptr ) { return ptr; }

#define NEW( T ) TrackNew<T>( new T )

struct X
{
     X() {}
     X( int ) {}
};

int main()
{
     // Works fine.
     X* p1 = NEW( X );

     // Fails to compile.
     X* p2 = NEW( X( 2 ) );

     return 0;
}

The second use of the NEW macro expands to:

X* p2 = TrackNew<X( 2 )>( new X( 2 ) );

Obviously, this should be:

X* p2 = TrackNew<X>( new X( 2 ) );

Can anyone please tell me a portable way of getting rid of the
new-initializer in the new-expression? Like in the following pseudo code:

#define NEW( T ) TrackNew<REMOVE_NEW_INITIALIZER( T )>( new T )


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?

HTH,

Ganesh

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