Path: utzoo!utgpu!water!watmath!clyde!att-cb!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!umd5!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.unix.wizards
Subject: Re: Pty ports and TIOCUCNTL mode
Message-ID: <7715@brl-smoke.ARPA>
Date: 17 Apr 88 02:01:21 GMT
References: <576@modular.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Distribution: comp
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 11

In article <576@modular.UUCP> olson@modular.UUCP (Jon Olson) writes:
>Does anyone know anything about the TIOCUCNTL mode for Unix pty ports?

ioctl(fd, TIOCUCNTL, &flag) enables (if flag nonzero) or disables (if flag zero)
the transmission of ioctl information through a pty.  Unfortunately only one byte
of ioctl information can be transmitted per ioctl.

The main use of TIOCUCNTL is for user-mode terminal multiplexing, as in the
"mpx" utility that supports AT&T Teletype 5620 or 630 dot-mapped display
terminals in their "layers" mode of operation.  It is the analogue of JSMPX
in the "xt" kernel-multiplexing version.