[Interest] QList operator[]

[K. Frank]

Hi Thiago!

On Sat, Jan 10, 2015 at 1:56 PM, Thiago Macieira
<thiago.macieira at intel.com> wrote:
> On Saturday 10 January 2015 12:19:26 K. Frank wrote:
>> > Seems odd behaviour to
>> > get from a couple of lines of code like that.  Would never have expected
>> > that to be a memory leak!
>>
>> I agree that something odd is going on here.  I understand why you
>> got a deep copy that you didn't anticipate, but I don't see why that
>> would lead to a memory leak.
>>
>> I'm hoping that the experts can shed some more light on this issue.
>
> There is no leak.

Would you care to elaborate?

According to Brad:

   I added a couple lines of code to an app and suddenly it started
   chewing through memory at an unbelievable rate.  I watched it
   get up to 12 GB at which point it hit my virtual memory limit ...

One of the added lines was:

   const CultureItem& it = culture.items[i]; // added this

This is a variable local in scope to a for-loop.  It seems unlikely
that a *single* deep copy of culture.items[i] would eat up 12+ GB,
and -- barring my misunderstanding of some C++ issue -- since
"it" goes out of scope at the end of the loop, only one deep copy
should exist at a time.

The symptoms Brad describes sure sound like a leak, so I would
like to understand your analysis of the situation.

> Thiago Macieira - thiago.macieira (AT) intel.com


Best.


K. Frank