R help - Aug 2004 - load shared object

Hi all,
i have some problem in using shared objects.
I tried the example found in "Writing R Extension", pg. 33

I used the .c file prova.c :

-------------------------------------------------------------------
#include <R.h>
#include <Rinternals.h>

void convolve(double *a, int *na, double *b, int *nb, double *ab)
{
	int i, j , nab = *na + *nb - 1;
	
	for (i = 0; i < nab; i++)
		ab[i] = 0.0;
	for (i = 0; i < *na; i++)
		for (j = 0; i < *nb; i++)
			ab[i + j] += a[i] * b [j];
}
-------------------------------------------------------------------

I generated shared object with 
R CMD SHLIB prova.c

i run R and so
> dyn.load("prova.so", local = TRUE, now = TRUE)
>convolve1<-function(a,b).C("convolve",as.double(a),as.integer(length(a)),as.double(b),as.integer(length(b)),ab
= double(length(a) + length(b) - 1)$ab)
> a<-1:10
> b<-a
typing convolve1(a,b) i get a Segmentation fault.

Can anyone tell me what's the problem

Regards

-- 
Federico Cantini <cantini at ifc.cnr.it>

Which version of R is this?  (See the posting guide, please.)

Some versions of R (e.g. 1.8.0) already had "convolve" loaded and you
need
to use another name or use the PACKAGE argument.  It works in the current
1.9.1.

On Wed, 4 Aug 2004, Federico Cantini wrote:
> Hi all,
> i have some problem in using shared objects.
> I tried the example found in "Writing R Extension", pg. 33
> 
> I used the .c file prova.c :
> 
> -------------------------------------------------------------------
> #include <R.h>
> #include <Rinternals.h>
> 
> void convolve(double *a, int *na, double *b, int *nb, double *ab)
> {
> 	int i, j , nab = *na + *nb - 1;
> 	
> 	for (i = 0; i < nab; i++)
> 		ab[i] = 0.0;
> 	for (i = 0; i < *na; i++)
> 		for (j = 0; i < *nb; i++)
> 			ab[i + j] += a[i] * b [j];
> }
> -------------------------------------------------------------------
> 
> I generated shared object with 
> R CMD SHLIB prova.c
> 
> i run R and so
> 
> > dyn.load("prova.so", local = TRUE, now = TRUE)
> 
>
>convolve1<-function(a,b).C("convolve",as.double(a),as.integer(length(a)),as.double(b),as.integer(length(b)),ab
= double(length(a) + length(b) - 1)$ab)
> 
> > a<-1:10
> > b<-a
> 
> typing convolve1(a,b) i get a Segmentation fault.
> 
> Can anyone tell me what's the problem
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595