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From: dce@quacky.UUCP (David Elliott)
Newsgroups: comp.unix.wizards
Subject: Re: stuff chars
Message-ID: <104@quacky.UUCP>
Date: Thu, 4-Dec-86 00:34:05 EST
Article-I.D.: quacky.104
Posted: Thu Dec  4 00:34:05 1986
Date-Received: Fri, 5-Dec-86 06:10:25 EST
References: <19@houligan.UUCP> <2270@sdcsvax.UCSD.EDU>
Reply-To: dce@quacky.UUCP (David Elliott)
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 30

In article <2270@sdcsvax.UCSD.EDU> hutch@sdcsvax.UUCP (Jim Hutchison) writes:
>...
>
>I suggest sending "\n:stop\n" to stop vi, this should circumvent that
>flushing problem you get with just sending ^Z to vi and letting it deal
>with the intterupt.  This also gets around the problem of having the
>stop character set to something other than ^Z (heaven forbid! :-)

If you look at the code for ex, you will notice that ^Z and :stop are
handled in the same way. That is, the onsusp() routine is called, which
just resets the SIGTSTP handler to SIG_DFL, and sends a SIGTSTP to the
current process. You can't stop a process in BSD Unix without a signal.

In other words, the only difference between ^Z and :stop is what you
type. The reason to have :stop is so that you can typeahead long
before you enter vi. For example, let's say you are executing some
command to create a file that you then need to edit. You might execute
the original command in the foreground, type in a couple of more commands,
type in the vi command, and some vi commands (such as a search for a
pattern). At this point, you realize that you will need to read a
manual page. If you type ^Z, you stop now and lose the input you typed
ahead. If you type :stop, you will enter vi and stop. Loss of typeahead
can really be a pain (this makes the Apollo Domain/IX version of vi,
and some of the nicer shell line editors not worth using).

I have never found a way to change the handling of signals such that
input is not flushed.

			David
			decwrl!mips!dce