how to restrict the numbers of chars in a buffer/file

[Stephen J. Turnbull]

>>>>> "Uwe" == Uwe Brauer <oub at mat.ucm.es> writes:

    Uwe> Thanks did not know about that one. Lets see whether I can
    Uwe> manage.

For your use case, David's suggestion is far better than mine (I
focused on the "file" in "buffer/file").  Something very simple like

(defvar uwe-message-limit 155)

(lambda (&rest ignored)        ; you may need to have correct
                               ; dummy arguments here
  (when (> (buffer-size) uwe-message-limit)
    (warn "The message buffer has %d characters.
You should reduce it to %d characters or less."
           (buffer-size) uwe-message-limit)))

should do as the hook function.

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