Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!novavax!weiner
From: weiner@novavax.UUCP (Bob Weiner)
Newsgroups: comp.emacs
Subject: Problem with buffer object life in GNU Emacs Lisp
Message-ID: <1414@novavax.UUCP>
Date: 5 Aug 89 02:47:55 GMT
Organization: Nova University, Fort Lauderdale, FL
Lines: 28


If you do something like:

(setq rmail-summary-buffer (get-buffer "RMAIL-summary"))

and then kill the actual summary buffer, rmail-summary-buffer will now
reference a 'killed buffer' object.  Typical code uses get-buffer to
check if such a buffer exists, if it does not, get-buffer usually returns
nil.  The global reference rmail-summary-buffer prevents the object from
being garbage collected so (get-buffer "RMAIL-summary") still returns a
non-nil value and your conditional code fails.  But if you try to do
anything with typical operations on this killed buffer you get errors,
as you would expect.

If one made rmail-summary-buffer reference the buffer name instead of
the buffer object, there would be no problem, but often referencing the
object is preferred.

Is there a function such as 'get-non-killed-buffer' which solves this
problem or something else that I am missing?

This is all based on GNU Emacs 18.52.  Thanks for any help.
-- 
Bob Weiner, Motorola, Inc.,   USENET:  ...!gatech!uflorida!novavax!weiner
(407) 738-2087
-- 
Bob Weiner, Motorola, Inc.,   USENET:  ...!gatech!uflorida!novavax!weiner
(407) 738-2087