## ----c_sum---------------------------------------------------------------
c_sum <- function(x) 
    .C("c_sum", as.numeric(x), length(x), answer=numeric(1))$answer


## ----c_sum-invoke, eval=FALSE--------------------------------------------
## dyn.load("~/c_sum.so")
## c_sum(1:100)


## ----c-headers-----------------------------------------------------------
R.home("include")


## ----call_sum------------------------------------------------------------
call_sum <- function(x) .Call("call_sum", as.numeric(x))


## ----rccp-compile, eval=FALSE--------------------------------------------
## library(Rcpp)
## sourceCpp("~/rcpp_sum.cpp")


## ----eval=FALSE----------------------------------------------------------
## rcpp_sum(1:10)