Re: A new(?) warning of erase-buffer, which was not seen before.

[ishikawa]

Kim F. Storm wrote:
> ishikawa <address@hidden> writes:
>
> > Hi,
> >
> > When I ran "erase-buffer" on a buffer named "*sim*", I got
> > the following warning, which I didn't get with older version of Emacs.
> >
> > Is this warning an intentional one?
>
> Yes.
>
>
> > In the old emacs version(s), it used to be that erase-buffer intentionally
> > discarded undo information if I recall correctly. 
>
> I just checked, and no version of GNU Emacs since 1991 has done that
> (I didn't check older versions).
>
> >                                                   The buffer in question, namely
> > "*sim*",  contained
> > a voluminous output of a running simulator program and I simply want to
> > throw away the contents from time to time. And thus, undo is not necessary
> > for this buffer.
>
> So disable undo in that buffer.

Thank you for the info.

It is only that I am a little puzzled that I didn't get this warning
in the previous versions 21.x (and prior), and I am wondering
if there is a better memory allocation/checking introduced in 22.0
which causes this warning to appear. In the older versions, say 21.x (and 
prior), I have not seen this message.
With 22.0, I see the memory usage warning also, which I didn't notice often 
before.

Maybe, with the older versions, the logic to show the warning might have had a 
subtle bug/feature which caused the warning not to  appear often on my PC. But I 
digress.

I will disable undo on this buffer and move on.
(Maybe my knowledge of erase-buffer discarding undo information is
based on the old knowledge of 18.xx version which I tried to port
to now extinct Data General minicomputers. This was circa mid 1980's)

Thank you again.

Chiaki Ishikawa