On 12/01/2008 2:13 PM, Edna Bell wrote:> Dear R Gurus:
>
> I'm reading through the "Writing R Extensions" manual.
>
> I am seeing references to "load hooks" and SEXPR but have no
ideas
> what these are.
>
> Could someone give me some direction as to finding out about these, please?
SEXP is the name in the C language for the type that stores a pointer to
an R object. Usually you use the macros defined in Rinternals.h and R.h
(and headers they load). The definition of the internal structure is
also there, but you normally don't need to make use of it.
Load hooks have their own section in the R Extensions manual. They are
functions that are called at the time packages (or other things) are
loaded, so they can do initialization, etc.
If you really want to look at the gory details, see the R Internals
manual. You rarely need to look there, but when you need it, you can
probably trust that manual to be more accurate than the others, which
sometimes fall out of date in some details.
Duncan Murdoch