[no subject]

[Glenn S. Burke <GSB at MIT-ML>]

If there is no errset or the error will be stacked anyway because of
the setting of the variable ERRSET, then the error-handling function
gets called, and it prints the error message itself, using the
ERRPRINT function.  If the error is not going to be stacked, then
if the errset specified that the error should be printed, it is printed
using ERRPRINT (effectively), without going into the handler, and the
errset thrown to.  The result of this is that with errset one might
not get specially-formatted error messages because the handler doesn't
get called at all.  Conversely, if you arrange for the handler to get
called by (setq errset 'car) or somesuch nonsense, it has no way of
finding out if it should print the message or not, or enter debugger
or break loop or not.