Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!rutgers!ukma!xanth!nic.MR.NET!srcsip!quasar!alarson
From: alarson@quasar.SRC.Honeywell.COM (Aaron Larson)
Newsgroups: gnu.emacs.bug
Subject: Re: minor bug in 18.52 rmail-message-labels-p
Message-ID: <19389@srcsip.UUCP>
Date: 27 Mar 89 00:30:47 GMT
References: <19095@srcsip.UUCP> <985@rpi.edu>
Sender: news@src.honeywell.COM
Lines: 15
In-reply-to: weltyc@cs.rpi.edu's message of 24 Mar 89 05:49:19 GMT

In article <985@rpi.edu> weltyc@cs.rpi.edu (Christopher A. Welty) writes:
   A couple of things: 
   ...
   4) unwind-protect is very important and does something completely
   different than save-restriction, it protects you from errors.  If
   there is an error in the middle of a save-restriction (or excursion)
   you don't you back to the state you were trying to save.
   unwind-potect insures that even if there is an error you will do some
   finishing up before you return, so ie you can narrow your buffer
   again.  Clear or not it's quite important.

It was my impression that save-restriction did an unwind-protect.  The
documentation for it does not say that it does, but according to the source
it does.  Your other points are well taken, and supported by the
documentation.  It pays to read...