tclx_errorHandler message
     The tclx_errorHandler command doesn't exist as built-in part
     of  TclX.   Instead,  individual applications or  users  can
     define  a tclx_errorHandler  command (e.g.  as  a  Tcl  pro-
     cedure)  if  they  wish to handle uncaught errors.  The pro-
     cedure will be passed a single argument of  the  error  mes-
     sage,  with errorCode and errorInfo having values reflecting
     the error that occurred.

     The tclx_errorHandler command is called when an  error  that
     is not caught returns to the top level command evaluation in
     the  TclX  shell   or   wishx.    The   difference   between
     tclx_errorHandler  and  bgerror is that tclx_errorHandler is
     called during the synchronous execution of  a  script  while
     bgerror  is  called  as  a result of an uncaught error in an
     event  handler.   In  a  non-event   oriented   Tcl   script
     tclx_errorHandler  will be called on all errors that are not
     caught and bgerror is not used.  In a wishx script or  event
     oriented    script    executed    with   the   TclX   shell,
     tclx_errorHandler will be called on uncaught  errors  during
     the  execution  of  the  main  script  that set up the event
     oriented program.  Once the event loop is  entered,  bgerror
     will be called on uncaught errors.

     This procedure is not called in response to commands entered
     via an interactive command loop, only from the evaluation of
     scripts or Tcl commands passed via the command line.  If the
     procedure  returns  normally,  the  program  will  just exit
     without any error being issued by the shell.  Generally  the
     procedure  should  exit  with  a non-zero exit code once the
     error has been processed.  It is not  possible  to  continue
     executing  the  code  in  which the error occurred.  This is
     useful for logging errorInfo or e-mailing it  to  the  main-
     tainer.