% TTFETCH   Fetch a message from a mailbox (blocking)%%  Usage: ttFetch(mailboxname)%%  Inputs:%    mailboxname  Name of a mailbox.%%  Note:%    The actual message is read using TTRETRIEVE.%       % See also TTCREATEMAILBOX, TTTRYPOST, TTTRYFETCH, TTPOST, TTRETRIEVE%%       TrueTime, Version 1.4%       Copyright (c) 2006%       Martin Ohlin, Dan Henriksson and Anton Cervin%       Department of Automatic Control, LTH%       Lund University, Sweden