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c++visual-c++new-operatorcopy-constructorplacement-new

Does casting a pointer to "void*" have any effect when placement new is called?

I'm reviewing code of a custom container and some portions of it create elements like this:

::new( (void*)&buffer[index] ) CStoredType( other );

and some do like this:

::new( &buffer[index] ) CStoredType( other );

So both use placement new to invoke a copy constructor to create an element by copying some other element, but in one case a pointer to the new element storage is passed as is and in another it is casted to void*.

Does this cast to void* have any effect?

Solution

  • Yes you could overload operator new for a nonvoid pointer. The cast ensures that the void pointer overload is taken.

    For example

    void* operator new(size_t s, env * e);