strip!

/*
 *  call-seq:
 *     str.strip!   => str or nil
 *  
 *  Removes leading and trailing whitespace from <i>str</i>. Returns
 *  <code>nil</code> if <i>str</i> was not altered.
 */

static VALUE
rb_str_strip_bang(str)
    VALUE str;
{
    VALUE l = rb_str_lstrip_bang(str);
    VALUE r = rb_str_rstrip_bang(str);

    if (NIL_P(l) && NIL_P(r)) return Qnil;
    return str;
}