[Rd] How to maintain memory in R extension
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? Thanks, Da __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] How to maintain memory in R extension
Hi, I think you need external pointers: http://cran.r-project.org/doc/manuals/r-release/R-exts.html#External-pointers-and-weak-references The docs also has an example. See more examples from other R packages here: https://github.com/search?q=R_MakeExternalPtr+user%3Acrantype=Codeutf8=%E2%9C%93 Gabor On Wed, Nov 12, 2014 at 8:36 AM, Zheng Da zhengda1...@gmail.com 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? Thanks, Da __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] How to maintain memory in R extension
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 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Computational Biology / Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N. PO Box 19024 Seattle, WA 98109 Location: Arnold Building M1 B861 Phone: (206) 667-2793 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] How to maintain memory in R extension
Thank you, Gabor and Martin. It helps a lot. Da On Wed, Nov 12, 2014 at 1:20 PM, Martin Morgan mtmor...@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 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Computational Biology / Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N. PO Box 19024 Seattle, WA 98109 Location: Arnold Building M1 B861 Phone: (206) 667-2793 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
Re: [Rd] How to maintain memory in R extension
On Wed, Nov 12, 2014 at 10:20 AM, Martin Morgan mtmor...@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. A small but important addition: Make sure your registered finalizer also works, or at least don't core dump R, if your package (or one of its dependencies) happens be unloaded by the time the garbage collector runs. This task seems easy but can be quite tricky, e.g. should you reload you package temporarily and what are the side effects from doing that? /Henrik Martin Morgan Thanks, Da __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel -- Computational Biology / Fred Hutchinson Cancer Research Center 1100 Fairview Ave. N. PO Box 19024 Seattle, WA 98109 Location: Arnold Building M1 B861 Phone: (206) 667-2793 __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel __ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
