On 13 September 2018 at 08:51, Qiang Kou wrote: | Hi, Mounia, | | In Rcpp, using std::vector is preferred.
Building on what Qiang said: If your array is a simple double[] then you can switch to std::vector<double> easily as aligning your array with the internal array. (Ditto for most other arrays of base types.) Or conversely, your can use Rcpp and transfer data from R down to C++ code using a std::vector<double> and then access the address of the initial element for your pointer. But the better approach is to use std::vector<> (Or our Rcpp::NumericVector). One reason is that Rcpp uses the .Call() interface to R, and it does _not_ support plain C pointers. Only the older (and not recommended anymore) .C() interface does. But then you have to give up all of Rcpp as well ... | It is still possible to use pointers, however, I am afraid you need to | write your "as" and "wrap" by yourself. You can find how to develop them in | our documents. And as<>() and wrap() are really intended for more complex data structures and not for pointers to atomistic C types. And yes, you would have work to do for new types. Hope this helps, Dirk | Best, | | Qiang Kou | | On Thu, Sep 13, 2018 at 4:15 AM Mounia ZAOUCHE < | mounia.zaou...@agroparistech.fr> wrote: | | > | > Dear all. | > | > I write C++ programs and I'm currently trying to interface them with R. | > | > I have two issues : | > | > Is it possible to interface a function which has an argument that is a | > pointer (standing for an array) ? | > | > I also wrote a function whose aim is to allocate (and fill) an array of | > values. In this purpose, this function takes as an argument the address of | > the array to be allocated and is thus typed as a pointer of pointer. | > Is it possible to handle such a type and to allocate the required memory | > inside this function interfaced in R? | > | > Thank you in advance. | > | > Mounia Zaouche. | > | > _______________________________________________ | > Rcpp-devel mailing list | > Rcpp-devel@lists.r-forge.r-project.org | > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel | _______________________________________________ | Rcpp-devel mailing list | Rcpp-devel@lists.r-forge.r-project.org | https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel -- http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
