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From: dce@smsc.sony.com (David Elliott)
Newsgroups: comp.unix.questions
Subject: Re: BSD vs. SVR4 typehead flush after tty mode change
Message-ID: <1990Oct12.042534.10858@smsc.sony.com>
Date: 12 Oct 90 04:25:34 GMT
References: <10704@uudell.dell.com> <14028@smoke.BRL.MIL> <15042@cbmvax.commodore.com>
Organization: Sony Microsystems Corp, San Jose, CA
Lines: 18

>In article <14028@smoke.BRL.MIL> gwyn@smoke.BRL.MIL (Doug Gwyn) writes:
>>In article <10704@uudell.dell.com> jrh@mustang.dell.com (James Howard) writes:
>>My bet would be that "more" was improperly ported,
>>and that a "flushing" tty ioctl was used in the port.
>
>No.  There is a bug in SysVr4 streams tty module `ldterm' that flushes
>the stream if ICANON is turned on.

While this may be true, the problem with more in this case was that
it was using TCSETAF, which does flush the tty.  I don't know whether
or not this is "improper".  It doesn't work nicely for me, but it
may be the right thing to do for shl.

It also turned out that SVR4 more resets the tty even if it never
changed it in the first place.

I changed both (TCSETAF becomes TCSETA, and the mode is only reset
if it was changed).  Programs shouldn't mess around with my typeahead.