The RInside package provides a few classes for seamless embedding of R inside of C++ applications by relying on Rcpp.

Provided with the package itself are nine subdirectories with examples: from more than a dozen basic command-line examples (in directory standard) to graphical user-interfaces (using both Qt and Wt), linear algebra with Armadillo and Eigen, parallel computing with MPI to a sandboxed server, and (since release 0.2.16) a simple (and more limited) interface for embedding insice C applications.

The simplest example (modulo its header) is examples/standard/rinside_sample0.cpp

#include <RInside.h>                    // for the embedded R via RInside
int main(int argc, char *argv[]) {
    RInside R(argc, argv);              // create an embedded R instance
    R["txt"] = "Hello, world!\n";	    // assign a char* (string) to 'txt'
    R.parseEvalQ("cat(txt)");           // eval the init string, ignoring any returns
    exit(0);
}

The Qt example directory produces this application for showing how to use R (to estimate densities) inside a C++ executable (providing the GUI):

The code is portable across operating systems. Similar, the Wt example directory contains this C++-based web application doing the same:

The RInside web page has some more details.

Dirk Eddelbuettel, Romain Francois, and Lance Bachmeier

GPL (>= 2)