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Re: Is escaping of a temp variable valid?


On Mon, Aug 18, 2014 at 11:39 AM, Joey Ye <joey.ye.cc@gmail.com> wrote:
> On Fri, Aug 15, 2014 at 6:33 PM, Richard Biener
> <richard.guenther@gmail.com> wrote:
>> On Fri, Aug 15, 2014 at 10:45 AM, Joey Ye <joey.ye.cc@gmail.com> wrote:
>>> Running into an unexpected result with GCC with following case, but
>>> not sure if it is a valid C++ case.
>>>
>>> #define nullptr 0
>>> enum nonetype { none };
>>>
>>> template<typename T>
>>> class class_zoo {
>>>   public:
>>>     const T *data;
>>>     int length;
>>>
>>>     class_zoo (nonetype) : data (nullptr), length (0) {}
>>>     class_zoo (const T &e) : data (&e), length (1) {}
>>
>> Capturing a const referece via a pointer is error-prone as for
>> example literal constants class_zoo<const int *> zoo(0)
>> have associated objects that live only throughout the function
>> call.
> Thanks for confirming this. But do you imply capturing a non-const
> reference via a pointer is safe, which I would assume it unsafe
> either?

Well, "more" safe at least ;)

Richard.

> - Joey
>>
>> So clearly your testcase is invalid.
>>
>> Richard.


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