Re: using delete expression on global operator new allocated memory

"Alf P. Steinbach" <>
Wed, 30 Apr 2008 16:02:19 +0200
* dizzy:


I wonder if this code is standard conformant and should work on all
conformant implementations (for some type T):

1: void* mem = ::operator new(sizeof(T));
2: T* p = new(mem) T(args...);
3: delete p;

line 2 I know it should be fine because global operator new should return
memory aligned for any type. The thing I wonder about is line 3. Should
this always work?

PS: the code might seem silly, it is needed because I need to decouple the
point of storage type used (which on 2 different codepaths can be on stack
or dynamic) from the point of actual initialization of the object and its
arguments (thus I need to use placement new); another solution I am aware
of whould be using some kind of "factory functors" (like the ones in boost)
but that would require for me to use template functions which is what I
want to avoid in the first place

Yes, the code is silly.

Stack (or in C++ terminology local variable):

   int main()
      T o( args... );


   int main()
       std::auto_ptr<T> p( new T( args... ) );

Cheers, & hth.,

- Alf

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