Message is a string that is returned to the application to indicate what went wrong.
If the info argument is provided and is non-empty, it is used to initialize the global variable errorInfo . If the info argument is present, it is used to initialize errorInfo and the first increment of unwind information will not be added by the Tcl interpreter. If the code argument is present, then its value is stored in the errorCode global variable. The Regents of the University of California.