About 20% packages from CRAN and BIOC repositories include some native code and more than a half of those include some code in C++. This number is rather high given that the R API and runtime have been designed for C (or Fortran) and cannot be used reliably from C++, without extensive effort and restrictions. To avoid nasty bugs in such code, one needs to know R internals well, and when following the restrictions, one cannot use much from C++ …