Hi Lille, To my understanding, there's no need to get the actual memory address of the R data frame, as using .Call() or .External() can be used in a "call by reference" way as well. This would be contrary to standard R behaviour, so if you use that in a package, make sure you indicate this!
There's a detailed explanation on how to deal with R objects in C code in the manual "Writing R extensions" here : https://cran.r-project.org/doc/manuals/R-exts.html#Handling-R-objects-in-C Especially check the section "Named objects and copying", which explains in more detail how to control the standard R behaviour. Also keep in mind that data frames are list-like structures, which are handled differently from atomic vectors. Hope this helps. Kind regards Joris On Thu, Jan 9, 2020 at 12:48 PM lille stor <lille.s...@gmx.com> wrote: > Hello, > > I would like for my C function to be able to manipulate some values stored > in an R data frame. > > To achieve this, a need the (real) memory address where the R data frame > stores its data (hopefully in a contiguous way). Then, from R, I call the C > function and passing this memory address as a parameter. > > The question: how can we get the memory address of the R data frame? > > Thank you! > > L. > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > -- Joris Meys Statistical consultant Department of Data Analysis and Mathematical Modelling Ghent University Coupure Links 653, B-9000 Gent (Belgium) <https://maps.google.com/?q=Coupure+links+653,%C2%A0B-9000+Gent,%C2%A0Belgium&entry=gmail&source=g> ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
