[R] simple example of C interface to R

[jbdunsmo@utmb.edu]

i'd like to use the C interface to R in a program i'm writing.  as a
starting point, i'm trying to create a very simple C program that uses
R.  i've read the R documentation on this, but i'm having trouble
figuring out where SEXP is defined and how to use it.

i noticed someone else on this list also tried to use the C interface,
but they ran into similar problems:
http://maths.newcastle.edu.au/~rking/R/help/03b/1942.html

could someone show me a simple example of how to use the R interface
to C?

thank you,
jason dunsmore