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 procedure) if they wish
to handle uncaught errors.  The procedure will be passed a single
argument  of  the  error  message,  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
