[R] for help on building a R package with several R function and a bunch of c, c++

[alex46015 at yahoo.com]

Hope I can get quick help from here, I have a bunch of c, c++ included main function and makefile. It works well on both UNIX and windows. I tried to build R package which include this C++ program and several other R functions.  R function here are independent  c++ code. I prefer to define one R function to call this c++ program.

Do you know any easy way to do it? I am reading manual "Writing R Extensions", I didn't catch the key point. I know how to build R package with just R function,  If I put all c++ code and makefile in /src...what I need do?

Thank you in advance!

Alex