It is possible to read .Rdata file format from C or Fortran?

Question

I\'m working writing some R extensions on C (C functions to be called from R).

My code needs to compute a statistic using 2 different datasets at the same time, and

Answer 1

It is not too hard to call R functions from C, using the .Call interface. So write an R function that inputs the data, and invoke that from C. When you're done with one file, UNPROTECT() the data you've read in. This is illustrated in the following

## function that reads my data in from a single file
fun <- function(fl)
    readLines(fl)

library(inline)  ## party trick -- compile C code from within R
doit <- cfunction(signature(fun="CLOSXP", filename="STRSXP", env="ENVSXP"), '
    SEXP lng = PROTECT(lang2(fun, filename)); // create R language expression
    SEXP ans = PROTECT(eval(lng, env));       // evaluate the expression
    // do things with the ans, e.g., ...
    int len = length(ans);
    UNPROTECT(2);                     // release for garbage collection
    return ScalarInteger(len);        // return something
')

doit(fun, "call.R", environment())

A simpler approach is to invert the problem -- read two data files in, then call C with the data.