Greetings,
I am trying to call simple C-code from R.
I am on Windows XP with RTools installed.
The C-function is
#include <R.h>
#include <Rinternals.h>
#include <Rmath.h>
#include <Rdefines.h>
// prevent name mangling
extern "C" {
SEXP __cdecl test(SEXP s){
SEXP result;
PROTECT(result = NEW_NUMERIC(1));
double* ptr=NUMERIC_POINTER(result);
double t = *REAL(s);
double u = t-floor(t)-0.5;
if(u>0) *ptr=-1+4*u; else *ptr=-1-4*u;
Rprintf("The value is %f", *ptr);
UNPROTECT(1);
return result;
}
};
It is compiled with
R CMD SHLIB source.c
with flag
MAKEFLAGS="CC=g++"
If I compile with the default flags I get an error message about an
undefined reference to "__gxx_personality_v0".
However when I call this code from R with
test <- function(t){
.Call("test",t)
}
dyn.load("./source.dll")
test(0)
dyn.unload("./source.dll")
then R crashes.
I have a vague idea of the issue of calling conventions and was hoping that
the __cdecl
specifier would force the appropriate convention.
I also have Cygwin installed as part of the Python(x,y) distribution but I
am assuming that
R CMD SHLIB source.c
calls the right compiler.
What could the problem be?
Many thanks,
Michael
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