/*
 * call-seq:
 *   strio.closed?    -> true or false
 *
 * Returns +true+ if *strio* is completely closed, +false+ otherwise.
 */
static VALUE
strio_closed(self)
    VALUE self;
{
    struct StringIO *ptr = StringIO(self);
    if (!CLOSED(ptr)) return Qfalse;
    return Qtrue;
}