R help - Oct 2003 - allocating memory in a C module (fwd)

I pressed ^X in the wrong window.  Here's the right code:


Here's some code that does a pointless example

In C:


#include "Rinternals.h"

/* function takes no arguments and returns an object */
SEXP pie(){

	int n;
	SEXP alist, avector;

	/* work out how long a list to return */
	n = 2;
	/* create the list */
	PROTECT(alist = allocVector(VECSXP, n));

	/* create the first vector and populate it */
	n = 4;
	PROTECT(avector = allocVector(INTSXP, n));
	INTEGER(avector)[0] = 3;
	INTEGER(avector)[1] = 1;
	INTEGER(avector)[2] = 4;
	INTEGER(avector)[3] = 1;
	/* stick it into the list */
	SET_VECTOR_ELT(alist, 0, avector);
	UNPROTECT(1);

       /* create the second vector and populate it */
        n = 4;
        PROTECT(avector = allocVector(INTSXP, n));
        INTEGER(avector)[0] = 5;
        INTEGER(avector)[1] = 9;
        INTEGER(avector)[2] = 2;
        INTEGER(avector)[3] = 7;
        /* stick it into the list */
        SET_VECTOR_ELT(alist, 1, avector);
        UNPROTECT(1);

	UNPROTECT(1);  /* alist*/
	return alist;

}


in R

dyn.load("pie.so")
.Call("pie")


	-thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle