modified buffer

[David Vinayak Wallace <Gumby@MCC-AI>]

    Date: Mon, 29 Jul 85 11:52 EDT
    From: Doug Dodds <DODDS@TENEX.SCRC.Symbolics.COM>

	Date: Fri, 26 Jul 85 21:26 CDT
	From: David Vinayak Wallace <Gumby@MCC-AI>

	In Symbolics 3640 Zwei in Release 6.0, MCC-Site 6.0, IP-TCP 29.0,
	microcode TMC5-IO4-ST506-MIC 319, on Lord Ganesh:

	1> Why do commands like c-X c-O set the modified bit even if they don't
	   change the buffer?

    c-X c-O doesn't in the development system, and never did, as far as I
    can remember.  In what circumstances did this happen to you, for which
    commands?

Try these out on sys:examples;-readme- text and calc-2 lisp (I chose
short files which I know you'll have):

Go to the end of the buffer with m->.  Then type c-X c-O.  Though the
buffer appears unmodified (and the point is in the same place, and that
place is still next to the last character in the buffer) the "*"
appears.  m-~ followed by c-X c-O makes the "*" reappear, which it
shouldn't do.  c-X c-O m-~ c-X c-O should ALWAYS leave the buffer
unmodified.

	2> Why can't I reset the unmodified bit on buffers which aren't
	   associated with files?

    Hmm, too many multiple negatives here; I take it you are asking why you
    can't remove the "modified" mark on non-file buffers, i.e., make the "+"
    disappear from that buffer's line in the Edit Buffers listing.

More annoyingly, if I create a buffer with e.g. c-X c-F, it has a "*" in
the mode line which cannot be switched off with m-~.  This seems even
less consistent.