memory allocation problem under linux

Scrive Prof Brian Ripley <ripley at stats.ox.ac.uk>:

You keep on sending similar messages -- this is at least the third.  You 
need to find out where the segfault is occurring using gdb, and you have 
not told us.

Sorry for the repeated post (in 2 different mailing lists).
Tnx for your suggestion. Now I think I've found the problem. Try this:
////file foo.c
#include <R.h>
int **box;
void foo(){
  int i;
  box =   (int**)R_alloc(1,   sizeof(int *));
}
/////////////
Compiled with R CMD SHLIB foo.c
In R:

dyn.load("foo.so")
.C("foo")

*Segmentation fault*
The problem disappears when the declaration of 'box' comes inside the function
foo... Is this a bug?

Antonio, Fabio Di Narzo.