#include <sys/types.h>
extern char end;

static caddr_t curbrk = &end;
caddr_t sbrk();

caddr_t
sbrk(n)
     int n;
{ int res;
  if (n==0) return curbrk;
  { caddr_t x=curbrk;
    char *p;
    p=curbrk;
    p=p+n;
    res = brk(p);
  
    if (res==-1) error("can't set brk");
    else curbrk = p;
    return (x);}
}