[Rd] How to maintain memory in R extension

[Zheng Da]

Thank you, Gabor and Martin. It helps a lot.

Da

On Wed, Nov 12, 2014 at 1:20 PM, Martin Morgan <mtmorgan at fredhutch.org> wrote:
> On 11/12/2014 05:36 AM, Zheng Da wrote:
>>
>> Hello,
>>
>> I wrote a system to perform data analysis in C++. Now I am integrating
>> it to R. I need to allocate memory for my own C++ data structures,
>> which can't be represented by any R data structures. I create a global
>> hashtable to keep a reference to the C++ data structures. Whenever I
>> allocate one, I register it in the hashtable and return its key to the
>> R code. So later on, the R code can access the C++ data structures
>> with their keys.
>>
>> The problem is how to perform garbage collection on the C++ data
>> structures. Once an R object that contains the key is garbage
>> collected, the R code can no longer access the corresponding C++ data
>> structure, so I need to deallocate it. Is there any way that the C++
>> code can get notification when an R object gets garbage collected? If
>> not, what is the usual way to manage memory in R extensions?
>
>
> register a finalizer that runs when there are no longer references to the R
> object, see ?reg.finalizer or the interface to R and C finalizers in
> Rinternals.h. If you return more than one reference to a key, then of course
> you'll have to manage these in your own C++ code.
>
> Martin Morgan
>
>
>>
>> Thanks,
>> Da
>>
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>
>
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