pointer=

/*
 * call-seq: pos=(n)
 *
 * Modify the scan pointer.
 *
 *   s = StringScanner.new('test string')
 *   s.pos = 7            # -> 7
 *   s.rest               # -> "ring"
 */
static VALUE
strscan_set_pos(VALUE self, VALUE v)
{
    struct strscanner *p;
    long i;

    GET_SCANNER(self, p);
    i = NUM2INT(v);
    if (i < 0) i += S_LEN(p);
    if (i < 0) rb_raise(rb_eRangeError, "index out of range");
    if (i > S_LEN(p)) rb_raise(rb_eRangeError, "index out of range");
    p->curr = i;
    return INT2NUM(i);
}