On Sep 7, 2013, at 1:03 PM, Marc Glisse <marc.gli...@inria.fr> wrote:
> On Sat, 7 Sep 2013, Mike Stump wrote:
>
>>
>> On Sep 7, 2013, at 12:37 PM, Gabriel Dos Reis
>> <g...@integrable-solutions.net> wrote:
>>
>>> On Sat, Sep 7, 2013 at 2:27 PM, Marc Glisse <marc.gli...@inria.fr> wrote:
>>>> On Sat, 7 Sep 2013, Mike Stump wrote:
>>>>
>>>>> On Sep 7, 2013, at 3:33 AM, Marc Glisse <marc.gli...@inria.fr> wrote:
>>>>>>
>>>>>> this patch teaches the compiler that operator new, when it can throw,
>>>>>> isn't allowed to return a null pointer.
>>>>>
>>>>>
>>>>> You sure:
>>>>>
>>>>> @item -fcheck-new
>>>>> @opindex fcheck-new
>>>>> Check that the pointer returned by @code{operator new} is non-null
>>>>> before attempting to modify the storage allocated. This check is
>>>>> normally unnecessary because the C++ standard specifies that
>>>>> @code{operator new} only returns @code{0} if it is declared
>>>>> @samp{throw()}, in which case the compiler always checks the
>>>>> return value even without this option. In all other cases, when
>>>>> @code{operator new} has a non-empty exception specification, memory
>>>>> exhaustion is signalled by throwing @code{std::bad_alloc}. See also
>>>>> @samp{new (nothrow)}.
>>>>>
>>>>> ?
>>>>
>>>>
>>>> Thanks, I didn't know that option. But it doesn't do the same.
>>>
>>> Indeed.
>>
>> Can this throw:
>>
>> void *operator new (long unsigned int s) {
>> return 0;
>> }
>>
>> ? Is this allowed to return 0?
>
> I think using this function is illegal.
Yes, according the the standard, and without any compilation flags, it is.
However, with -fcheck-new and in the g++ language, it is not.
