operator new[] and operator delete[]

Daniel Lohmann daniel.lohmann@informatik.uni-erlangen.de
Mon Jul 30 21:41:00 GMT 2007


Wesley Smith schrieb:
> Hi,
> I've overloaded the new, delete, new[] and delete[] operators in a C++
> class defined as:
> 
> static void * operator new (size_t size);
> 		static void operator delete (void *p);
> 		
> 		static void * operator new[] (size_t size);
> 		static void operator delete[] (void *p);
> 
> 
> I've noticed if I do:
> 
> Object *o = new Object[100];
> 
> It calls new[] but if I do
> 
> delete o;
> 
> later it calls delete and therefore isn't symmetrical.  How can I get
> delete[] called?

Um... by calling it:

delete[] o;

It is part of the C++ language specification that arrays have to be 
destroyed with operator delete[]. This comes from the syntactic ambiguity 
between pointers and arrays. The compiler just cannot know if your o points 
to a single element of type Object or an array of type Object, so we have 
to tell him. If you use delete instead of delete[], only the first element 
gets actually destructed (even though the memory of all elements is freed).

Daniel



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