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

[Uwe Brauer]

>>>>> "David" == David Kastrup <dak at gnu.org> writes:

   David> Uwe Brauer <oub at mat.ucm.es> writes:
   >> Hello
   >> 
   >> Is there any possibility that a given buffer/file only admits say 150
   >> chars but not more?


   David> So cut down any changes to 150 characters here.

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