Re: [boost] [boost.test] Non-conforming operator new, AFAICT

From: Daniel Frey (d.frey_at_[hidden])
Date: 2005-12-28 06:19:01

Markus Schöpflin wrote:
> Daniel Frey wrote:
> 
> 
>>Markus Schöpflin wrote:
>>
>>
>>>boost.test currently contains an assortment of new operators which IMO are 
>>>not conforming to the C++ std.
>>>
>>>The implementation basically looks like this:
>>>
>>>p = std::malloc(n);
>>>if (!p) throw std::bad_alloc();
>>>
>>>This ignores the fact the std::malloc() is allowed to return either 0 or 
>>>some unique pointer on zero sized requests, whereas a C++ allocation 
>>>function _must_ return a unique pointer for each zero sized request.
> 
> 
>>I think it is guaranteed that a C++ allocation request (operator new) is
>>never asked to allocate 0 bytes, thus the problem doesn't exist.
> 
> 
> I'm sorry to insist, but what makes you think this might be the case? I 
> have never ever heard of such a guarantee, but this of course doesn't mean 
> much. Could you please point me to some reference for this?

I think operator new is intended to be called by new T. As zero sized
types don't exist, operator new will never be called with n==0.

But there's nothing which prevents you from calling operator new
directly, so maybe it's even possible for operator new.

What do the experts say? Was this intended or is it a defect report? Or
am I missing something?

(Note: I'm not talking about operator new[], which can be asked to
allocate an array of zero objects as per 5.3.4/7)

Regards, Daniel