While debugging multithreaded programs (c.f. Chapter 12, Concurrency, Section 2.9, “GUARD”, Section 2.24, “REPLY”), it becomes important to realize whether a method is defined to be guarded or unguarded (see sub keywords GUARDED and UNGUARDED on the METHOD directive in Section 3.5, “::METHOD”, and the methods SETGUARDED and SETUNGUARDED of the Method class in Section 5.1.3, “Method Class”).