[sword-devel] swld.cpp at line 111 - is this a bug?

DM Smith dmsmith at crosswire.org
Wed Oct 12 05:13:35 MST 2016

> On Oct 12, 2016, at 3:22 AM, Jaak Ristioja <jaak at ristioja.ee> wrote:
> On 12.10.2016 10:02, Manfred Bergmann wrote:
>>> Am 12.10.2016 um 08:57 schrieb Jaak Ristioja <jaak at ristioja.ee>:
>>> On 12.10.2016 09:37, Manfred Bergmann wrote:
>>>>> On 12.10.2016 01:08, TS wrote:
>>>>>> Xcode was warning me that in PocketSword's Sword framework, swld.cpp at
>>>>>> line 111 with
>>>>>> "delete buf;"
>>>>>> may be wrong and it should perhaps be
>>>>>> "delete[] buf;"
>>>>>> instead. Is this correct? I looked at the code and I think Xcode is
>>>>>> correct in that the variable is an array and needs the brackets to
>>>>>> delete properly.
>>>>> Yes, Xcode has it correct. It should be `delete[] buf;`. This was also
>>>>> fixed in Sword++ in March.
>>>> Despite the warning, would but not be deleted completely?
>>> It is undefined behavior, as stated by § in C++11. However, the
>>> C++ draft at https://github.com/cplusplus/draft doesn't have this
>>> wording since e51a2152 [1] for some reason.
>> Yeah, don’t get me wrong. It should be corrected.
>> But is it indeed a memory leak or does the runtime still collect and destroy all array elements?
>> Depends on the runtime probably.
> It is undefined behavior (see http://stackoverflow.com/q/2397984/3919155 <http://stackoverflow.com/q/2397984/3919155>
> ). So as far as the C++ standard is concerned, this might yield
> different behavior depending on the toolchain, the runtime, the
> environment or the phase of the moon... There are also no defined bounds
> to what may happen: it may leak, crash, hang, corrupt memory, whatever...
> J

If I recall delete without the brackets will delete the object. That is the array. When called with the brackets will call delete on the elements in the array. In some cases the semantic difference does not matter, such as an array of char or int. I didn’t look at the code to see if it mattered here.

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