eval.c:9607
static VALUE
rb_thread_status(thread)
    VALUE thread;
{
    rb_thread_t th = rb_thread_check(thread);

    if (rb_thread_dead(th)) {
	if (!NIL_P(th->errinfo) && (th->flags & THREAD_RAISED))
	    return Qnil;
	return Qfalse;
    }

    return rb_str_new2(thread_status_name(th->status));
}
