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
