Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
/////////////////////////////////////////
// Sample for Embedding C++ into R //
/////////////////////////////////////////
//
// I keep forgetting how to do this so here's an example.
// If you're willing to use R's most primitive FFI interface,
// things are incredibly simple and easy to get going.
// -Brendan O'Connor (brenocon@gmail.com)
//
// Compile with, e.g. on mac:
// $ g++ -dynamic -bundle -I/Library/Frameworks/R.framework/Resources/include ext.cc -o ext.dylib
// And from R:
// > dynload("ext.dylib")
// > .C("hi")
// Hello Earth
// list()
//
// .C() is very low level. To pass data in and out, you get raw pointers
// to the internal vectors that R itself uses. I think.
//
// > .C("mul_2", as.integer(1:3), as.integer(3), as.integer(rep(-1,3)))
// [[1]]
// [1] 1 2 3
//
// [[2]]
// [1] 3
//
// [[3]]
// [1] 2 4 6
//
// Documentation: http://cran.r-project.org/doc/manuals/R-exts.html#Interface-functions-_002eC-and-_002eFortran
#include <R.h>
#include <iostream>
using namespace std;
extern "C" {
void hi()
{
cout << "Hello Earth" << endl;
}
void mul_2(int* numbers, int* n, int* output)
{
for (int i=0; i < *n; i++) {
output[i] = numbers[i] * 2;
}
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.