[Rcpp-devel] Exposed class works within cpp func, bombs via module

[Thell Fowler]

On Wed, Feb 26, 2014 at 12:26 PM, Thell Fowler <tbfowler4 at gmail.com> wrote:
> resend including list
>
> ---------- Forwarded message ----------
> From: Thell Fowler <tbfowler4 at gmail.com>
> Date: Wed, Feb 26, 2014 at 12:25 PM
> Subject: Re: [Rcpp-devel] Exposed class works within cpp func, bombs via module
> To: Dirk Eddelbuettel <edd at debian.org>
>
>
> On Wed, Feb 26, 2014 at 11:46 AM, Dirk Eddelbuettel <edd at debian.org> wrote:
>>
>> Thell,
>>
>> On 26 February 2014 at 09:46, Thell Fowler wrote:
>> |
>> | I'm getting::
>> |
>> | *** Error in `/usr/lib/rstudio/bin/rsession': malloc(): smallbin double linked
>> | list corrupted: 0x0000000003436090 ***--
>> |
>> | It is a small class for iterative compositions.  It looks like there's a
>> | bad_alloc between the R and C++ sides of things but I'm not quite sure what to
>> | check on it.  Are there any docs going into the scoping of module exposed
>> | classes?
>> |
>> | The example bomb is posted as a gist at:
>> |
>> | https://gist.github.com/Thell/9231866
>>
>> I only glanced at it, and my only hunch, based on fix with iterators I sent
>> someone in another context just yesterday, may be that maybe something is
>> going off with your use of iterators in next().
>>
>> Maybe worth trying as a straight vector version?  It's just guess.
>>
>> Dirk
>>
>> --
>> Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com
>
> Dirk,
>
> Thanks.  Indeed it looks like the state_iter is having the issue.
> I've updated the gist with some cout debugging and have captured::
>
>> C$composition()
> state.begin addr: 0x2c7c1d0
> state_iter addr: 0x2e23a50
> state_iter type: N9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEE
> state size:3
> Accessing comp sized:1
> [1] 3
>
>> # bad_alloc
>> # C$advance()
>
> begin() and state_iter _should be pointing to the same addr.  Now the
> question is why it doesn't.
>
>
> BTW - what was the fix/issue you tackled yesterday?  Possibly any relation?
> --
> Sincerely,
> Thell
>
>
> --
> Sincerely,
> Thell

Using the RCPP_MODULE defined make_ function  initializes the iterator
just fine, but without _any_ pointer manipulation when just returning
the std::vector the iterator is showing that it has been corrupted...

> # Test via R
> C <- make_Composition(3)
Initializing:
state.begin addr: 0x2e23a50
state_iter addr: 0x2e23a50

> C$composition()
state.begin addr: 0x3795ca0
state_iter addr: 0x2e23a50
state_iter type: N9__gnu_cxx17__normal_iteratorIPiSt6vectorIiSaIiEEEE
state size:3
Accessing comp sized:1

Nice to know it isn't the pointer manipulation, not so nice to know
the addr is blowing in the wind somewhere.

-- 
Sincerely,
Thell