|Function: Notify at least one of the threads waiting for CONDITION-VARIABLE. It is implementation-dependent whether one or more than one (and possibly all) threads are woken, but if the implementation is capable of waking only a single thread (not all are) this is probably preferable for efficiency reasons. The order of wakeup is unspecified and does not necessarily relate to the order that the threads went to sleep in. CONDITION-NOTIFY has no useful return value. In an implementation that does not support multiple threads, it has no effect.