## ----eval = FALSE-------------------------------------------------------------
#  build_shared_lib = function (object_names) {
#      # Change working directory so R finds the Makevars.
#      old_dir = setwd(box::file())
#      on.exit(setwd(old_dir))
#      exitcode = system2('R', c('CMD', 'SHLIB', paste0(object_names, '.c')))
#      stopifnot(exitcode == 0L)
#  }
#  
#  build_shared_lib('hello')

## ----eval = FALSE-------------------------------------------------------------
#  box::use(./c/`__setup__`)

## ----eval = FALSE-------------------------------------------------------------
#  libname = function (name) {
#      box::file(paste0(name, .Platform$dynlib.ext))
#  }

## ----eval = FALSE-------------------------------------------------------------
#  .on_load = function (ns) {
#      ns$dll = dyn.load(libname('hello'))
#  }

## ----eval = FALSE-------------------------------------------------------------
#  .on_unload = function (ns) {
#      dyn.unload(libname('hello'))
#  }

## ----eval = FALSE-------------------------------------------------------------
#  #' @export
#  hello_world = function (name) {
#      .Call(dll$hello_world, name)
#  }

## ----eval = FALSE-------------------------------------------------------------
#  box::use(./c)
#  c$hello_world('Rthur')