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question about "R get vector from C"

2 messages · Michael S, Uwe Ligges

Michael S
# 
Dear ALL-R helpers,

I want to let R get vector from c ,for example :numeric array ,vector .I saw 
some exmple like this :
/* useCall3.c                                    */
/* Getting an integer vector from C using .Call  */
#include <R.h>
#include <Rdefines.h>

SEXP setInt() {
   SEXP myint;
   int *p_myint;
   int len = 5;
   PROTECT(myint = NEW_INTEGER(len));  // Allocating storage space
   p_myint = INTEGER_POINTER(myint);
   p_myint[0] = 7;
   UNPROTECT(1);
   return myint;
}

then type at the command prompt:
R CMD SHLIB useCall3.c
to get useCall3.so
In windows platform ,how can I create right dll to let dyn.load use
and for .c ,.call ,external ,what are the differece? which one is better for 
  getting vector from C?

thanks in advance

Michael
Uwe Ligges
#
Michael S wrote:
For the code above you certainly want to use .Call(), .C() and won't 
work with SEXP.
Under Windows, you can also say
   R CMD SHLIB useCall3.c
and get the corresponding useCall3.dll instead of useCall3.so. 
dyn.load() also works as expected, you just need the relevant tools / 
compiler installed.

Uwe Ligges