X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/blobdiff_plain/0f4556f12c8f75078501c9d1338ae7648a97f975..95f51977ddc18faa2e212f30c00a39540b39f325:/usr/man/man4/pty.4

diff --git a/usr/man/man4/pty.4 b/usr/man/man4/pty.4
index 7d3f14cc72..1e0d591e74 100644
--- a/usr/man/man4/pty.4
+++ b/usr/man/man4/pty.4
@@ -1,9 +1,15 @@
-.TH PTY 4 "7 July 1983"
-.UC 4
+.\" Copyright (c) 1983 Regents of the University of California.
+.\" All rights reserved.  The Berkeley software License Agreement
+.\" specifies the terms and conditions for redistribution.
+.\"
+.\"	@(#)pty.4	6.2 (Berkeley) 5/19/86
+.\"
+.TH PTY 4 "May 19, 1986"
+.UC 5
 .SH NAME
 pty \- pseudo terminal driver
 .SH SYNOPSIS
-.B pseudo-device pty
+.B pseudo-device pty [ count ]
 .SH DESCRIPTION
 The
 .I pty
@@ -28,8 +34,9 @@ given to the slave device as input and anything written
 on the slave device is presented as input on the master
 device.
 .PP
-In configuring, if no optional ``count'' is given in
-the specification, 16 pseudo terminal pairs are configured.
+In configuring, if an optional ``count'' is given in
+the specification, that number of pseudo terminal pairs are configured;
+the default count is 32.
 .PP
 The following 
 .I ioctl
@@ -82,6 +89,11 @@ TIOCPKT_NOSTOP
 whenever the start and stop characters are not ^S/^Q.
 .RE
 .IP
+While this mode is in use, the presence of control status information
+to be read from the master side may be detected by a
+.I select
+for exceptional conditions.
+.IP
 This mode is used by
 .IR rlogin (1C)
 and
@@ -90,6 +102,34 @@ to implement a remote-echoed, locally ^S/^Q flow-controlled
 remote login with proper back-flushing of output; it can be
 used by other similar programs.
 .TP
+TIOCUCNTL
+Enable/disable a mode that allows a small number of simple user
+.I ioctl
+commands to be passed through the pseudo-terminal,
+using a protocol similar to that of TIOCPKT.
+The TIOCUCNTL and TIOCPKT modes are mutually exclusive.
+This mode is enabled from the master side of a pseudo terminal
+by specifying (by reference)
+a nonzero parameter and disabled by specifying (by reference)
+a zero parameter.
+Each subsequent 
+.I read 
+from the master side will return data written on the slave part of
+the pseudo terminal preceded by a zero byte,
+or a single byte reflecting a user control operation on the slave side.
+A user control command consists of a special
+.I ioctl
+operation with no data; the command is given as UIOCCMD(\fIn\fP),
+where \fIn\fP is a number in the range 1-255.
+The operation value \fIn\fP will be received as a single byte on the next
+.I read
+from the master side.
+The \fIioctl\fP UIOCCMD(0) is a no-op that may be used to probe for
+the existence of this facility.
+As with TIOCPKT mode, command operations may be detected with a
+.I select
+for exceptional conditions.
+.TP
 TIOCREMOTE
 A mode for the master half of a pseudo terminal, independent
 of TIOCPKT.  This mode causes input to the pseudo terminal
@@ -108,5 +148,3 @@ is required.
 /dev/tty[p-r][0-9a-f]	slave pseudo terminals
 .SH DIAGNOSTICS
 None.
-.SH BUGS
-It is not possible to send an EOT.