INTERFACEErrLog ; IMPORT Wr; PROCEDURE Note (msg: TEXT); PROCEDURE Msg (a, b, c, d: TEXT := NIL); PROCEDURE Redirect (wr: Wr.T); PROCEDURE CancelRedirect (); VAR (* READONLY, LL = log_mu *) log_mu : MUTEX; log : ARRAY [0..499] OF TEXT; log_head : INTEGER := 0; log_len : INTEGER := 0; (* the last few logged messages, kept in a circular queue. *) END ErrLog.