1994-05-30 19:09:18 +00:00
|
|
|
.\" Copyright (c) 1991, 1992, 1993
|
|
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
|
|
.\"
|
|
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
|
|
.\" modification, are permitted provided that the following conditions
|
|
|
|
.\" are met:
|
|
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
|
|
.\" must display the following acknowledgement:
|
|
|
|
.\" This product includes software developed by the University of
|
|
|
|
.\" California, Berkeley and its contributors.
|
|
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
|
|
.\" may be used to endorse or promote products derived from this software
|
|
|
|
.\" without specific prior written permission.
|
|
|
|
.\"
|
|
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
|
|
.\" SUCH DAMAGE.
|
|
|
|
.\"
|
|
|
|
.\" @(#)termios.4 8.4 (Berkeley) 4/19/94
|
1999-08-28 00:22:10 +00:00
|
|
|
.\" $FreeBSD$
|
1994-05-30 19:09:18 +00:00
|
|
|
.\"
|
|
|
|
.Dd April 19, 1994
|
|
|
|
.Dt TERMIOS 4
|
2001-07-10 15:31:11 +00:00
|
|
|
.Os
|
1994-05-30 19:09:18 +00:00
|
|
|
.Sh NAME
|
|
|
|
.Nm termios
|
|
|
|
.Nd general terminal line discipline
|
|
|
|
.Sh SYNOPSIS
|
2001-10-01 16:09:29 +00:00
|
|
|
.In termios.h
|
1994-05-30 19:09:18 +00:00
|
|
|
.Sh DESCRIPTION
|
|
|
|
This describes a general terminal line discipline that is
|
|
|
|
supported on tty asynchronous communication ports.
|
|
|
|
.Ss Opening a Terminal Device File
|
|
|
|
When a terminal file is opened, it normally causes the process to wait
|
2003-06-28 23:53:39 +00:00
|
|
|
until a connection is established.
|
|
|
|
For most hardware, the presence
|
1994-05-30 19:09:18 +00:00
|
|
|
of a connection is indicated by the assertion of the hardware
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv CARRIER
|
|
|
|
line.
|
1994-05-30 19:09:18 +00:00
|
|
|
If the termios structure associated with the terminal file has the
|
|
|
|
.Dv CLOCAL
|
|
|
|
flag set in the cflag, or if the
|
|
|
|
.Dv O_NONBLOCK
|
|
|
|
flag is set
|
|
|
|
in the
|
|
|
|
.Xr open 2
|
|
|
|
call, then the open will succeed even without
|
|
|
|
a connection being present.
|
|
|
|
In practice, applications
|
|
|
|
seldom open these files; they are opened by special programs, such
|
|
|
|
as
|
1996-04-07 00:06:21 +00:00
|
|
|
.Xr getty 8
|
1994-05-30 19:09:18 +00:00
|
|
|
or
|
1996-04-07 00:06:21 +00:00
|
|
|
.Xr rlogind 8 ,
|
1994-05-30 19:09:18 +00:00
|
|
|
and become
|
|
|
|
an application's standard input, output, and error files.
|
|
|
|
.Ss Job Control in a Nutshell
|
|
|
|
Every process is associated with a particular process group and session.
|
|
|
|
The grouping is hierarchical: every member of a particular process group is a
|
2003-06-28 23:53:39 +00:00
|
|
|
member of the same session.
|
|
|
|
This structuring is used in managing groups
|
1994-05-30 19:09:18 +00:00
|
|
|
of related processes for purposes of
|
|
|
|
.\" .Gw "job control" ;
|
|
|
|
.Em "job control" ;
|
|
|
|
that is, the
|
|
|
|
ability from the keyboard (or from program control) to simultaneously
|
|
|
|
stop or restart
|
|
|
|
a complex command (a command composed of one or more related
|
2003-06-28 23:53:39 +00:00
|
|
|
processes).
|
|
|
|
The grouping into process groups allows delivering
|
1994-05-30 19:09:18 +00:00
|
|
|
of signals that stop or start the group as a whole, along with
|
|
|
|
arbitrating which process group has access to the single controlling
|
2003-06-28 23:53:39 +00:00
|
|
|
terminal.
|
|
|
|
The grouping at a higher layer into sessions is to restrict
|
1994-05-30 19:09:18 +00:00
|
|
|
the job control related signals and system calls to within processes
|
2003-06-28 23:53:39 +00:00
|
|
|
resulting from a particular instance of a
|
|
|
|
.Dq login .
|
|
|
|
Typically, a session
|
1994-05-30 19:09:18 +00:00
|
|
|
is created when a user logs in, and the login terminal is setup
|
|
|
|
to be the controlling terminal; all processes spawned from that
|
|
|
|
login shell are in the same session, and inherit the controlling
|
|
|
|
terminal.
|
1996-04-08 04:18:31 +00:00
|
|
|
.Pp
|
1994-05-30 19:09:18 +00:00
|
|
|
A job control shell
|
|
|
|
operating interactively (that is, reading commands from a terminal)
|
|
|
|
normally groups related processes together by placing them into the
|
2003-06-28 23:53:39 +00:00
|
|
|
same process group.
|
|
|
|
A set of processes in the same process group
|
|
|
|
is collectively referred to as a
|
|
|
|
.Dq job .
|
|
|
|
When the foreground process
|
1994-05-30 19:09:18 +00:00
|
|
|
group of the terminal is the same as the process group of a particular
|
2003-06-28 23:53:39 +00:00
|
|
|
job, that job is said to be in the
|
|
|
|
.Dq foreground .
|
|
|
|
When the process group of the terminal is different from the process group of
|
1994-05-30 19:09:18 +00:00
|
|
|
a job (but is still the controlling terminal), that job is said
|
2003-06-28 23:53:39 +00:00
|
|
|
to be in the
|
|
|
|
.Dq background .
|
|
|
|
Normally the
|
1994-05-30 19:09:18 +00:00
|
|
|
shell reads a command and starts the job that implements that
|
2003-06-28 23:53:39 +00:00
|
|
|
command.
|
|
|
|
If the command is to be started in the foreground (typical), it
|
1994-05-30 19:09:18 +00:00
|
|
|
sets the process group of the terminal to the process group
|
|
|
|
of the started job, waits for the job to complete, and then
|
|
|
|
sets the process group of the terminal back to its own process
|
2003-06-28 23:53:39 +00:00
|
|
|
group (it puts itself into the foreground).
|
|
|
|
If the job is to
|
1994-05-30 19:09:18 +00:00
|
|
|
be started in the background (as denoted by the shell operator "&"),
|
|
|
|
it never changes the process group of the terminal and doesn't
|
|
|
|
wait for the job to complete (that is, it immediately attempts to read the next
|
2003-06-28 23:53:39 +00:00
|
|
|
command).
|
|
|
|
If the job is started in the foreground, the user may
|
1994-05-30 19:09:18 +00:00
|
|
|
type a key (usually
|
|
|
|
.Ql \&^Z )
|
|
|
|
which generates the terminal stop signal
|
|
|
|
.Pq Dv SIGTSTP
|
2001-07-16 10:52:19 +00:00
|
|
|
and has the effect of stopping the entire job.
|
1994-05-30 19:09:18 +00:00
|
|
|
The shell will notice that the job stopped, and will resume running after
|
|
|
|
placing itself in the foreground.
|
|
|
|
The shell also has commands for placing stopped jobs in the background,
|
|
|
|
and for placing stopped or background jobs into the foreground.
|
|
|
|
.Ss Orphaned Process Groups
|
|
|
|
An orphaned process group is a process group that has no process
|
|
|
|
whose parent is in a different process group, yet is in the same
|
2003-06-28 23:53:39 +00:00
|
|
|
session.
|
|
|
|
Conceptually it means a process group that doesn't have
|
|
|
|
a parent that could do anything if it were to be stopped.
|
|
|
|
For example,
|
1994-05-30 19:09:18 +00:00
|
|
|
the initial login shell is typically in an orphaned process group.
|
|
|
|
Orphaned process groups are immune to keyboard generated stop
|
|
|
|
signals and job control signals resulting from reads or writes to the
|
|
|
|
controlling terminal.
|
|
|
|
.Ss The Controlling Terminal
|
2003-06-28 23:53:39 +00:00
|
|
|
A terminal may belong to a process as its controlling terminal.
|
|
|
|
Each
|
1994-05-30 19:09:18 +00:00
|
|
|
process of a session that has a controlling terminal has the same
|
2003-06-28 23:53:39 +00:00
|
|
|
controlling terminal.
|
|
|
|
A terminal may be the controlling terminal for at
|
|
|
|
most one session.
|
|
|
|
The controlling terminal for a session is allocated by
|
1994-05-30 19:09:18 +00:00
|
|
|
the session leader by issuing the
|
|
|
|
.Dv TIOCSCTTY
|
2004-07-03 18:29:24 +00:00
|
|
|
ioctl.
|
|
|
|
A controlling terminal
|
1994-05-30 19:09:18 +00:00
|
|
|
is never acquired by merely opening a terminal device file.
|
|
|
|
When a controlling terminal becomes
|
|
|
|
associated with a session, its foreground process group is set to
|
|
|
|
the process group of the session leader.
|
|
|
|
.Pp
|
|
|
|
The controlling terminal is inherited by a child process during a
|
|
|
|
.Xr fork 2
|
2003-06-28 23:53:39 +00:00
|
|
|
function call.
|
|
|
|
A process relinquishes its controlling terminal when it
|
1994-05-30 19:09:18 +00:00
|
|
|
creates a new session with the
|
1999-04-29 08:01:25 +00:00
|
|
|
.Xr setsid 2
|
1994-05-30 19:09:18 +00:00
|
|
|
function; other processes
|
|
|
|
remaining in the old session that had this terminal as their controlling
|
|
|
|
terminal continue to have it.
|
|
|
|
A process does not relinquish its
|
|
|
|
controlling terminal simply by closing all of its file descriptors
|
|
|
|
associated with the controlling terminal if other processes continue to
|
|
|
|
have it open.
|
|
|
|
.Pp
|
|
|
|
When a controlling process terminates, the controlling terminal is
|
|
|
|
disassociated from the current session, allowing it to be acquired by a
|
2003-06-28 23:53:39 +00:00
|
|
|
new session leader.
|
|
|
|
Subsequent access to the terminal by other processes
|
1994-05-30 19:09:18 +00:00
|
|
|
in the earlier session will be denied, with attempts to access the
|
|
|
|
terminal treated as if modem disconnect had been sensed.
|
|
|
|
.Ss Terminal Access Control
|
|
|
|
If a process is in the foreground process group of its controlling
|
|
|
|
terminal, read operations are allowed.
|
|
|
|
Any attempts by a process
|
|
|
|
in a background process group to read from its controlling terminal
|
|
|
|
causes a
|
|
|
|
.Dv SIGTTIN
|
|
|
|
signal to be sent to
|
|
|
|
the process's group
|
|
|
|
unless one of the
|
2004-07-03 18:29:24 +00:00
|
|
|
following special cases apply: if the reading process is ignoring or
|
1994-05-30 19:09:18 +00:00
|
|
|
blocking the
|
2000-05-09 14:02:06 +00:00
|
|
|
.Dv SIGTTIN
|
|
|
|
signal, or if the process group of the reading
|
1994-05-30 19:09:18 +00:00
|
|
|
process is orphaned, the
|
|
|
|
.Xr read 2
|
|
|
|
returns -1 with
|
|
|
|
.Va errno set to
|
2000-11-22 16:11:48 +00:00
|
|
|
.Er EIO
|
1994-05-30 19:09:18 +00:00
|
|
|
and no
|
2004-07-03 18:29:24 +00:00
|
|
|
signal is sent.
|
|
|
|
The default action of the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv SIGTTIN
|
|
|
|
signal is to stop the
|
|
|
|
process to which it is sent.
|
|
|
|
.Pp
|
|
|
|
If a process is in the foreground process group of its controlling
|
|
|
|
terminal, write operations are allowed.
|
|
|
|
Attempts by a process in a background process group to write to its
|
|
|
|
controlling terminal will cause the process group to be sent a
|
|
|
|
.Dv SIGTTOU
|
2004-07-03 18:29:24 +00:00
|
|
|
signal unless one of the following special cases apply: if
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv TOSTOP
|
|
|
|
is not
|
|
|
|
set, or if
|
|
|
|
.Dv TOSTOP
|
|
|
|
is set and the process is ignoring or blocking the
|
|
|
|
.Dv SIGTTOU
|
|
|
|
signal, the process is allowed to write to the terminal and the
|
|
|
|
.Dv SIGTTOU
|
2003-06-28 23:53:39 +00:00
|
|
|
signal is not sent.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv TOSTOP
|
|
|
|
is set, and the process group of
|
|
|
|
the writing process is orphaned, and the writing process is not ignoring
|
|
|
|
or blocking
|
|
|
|
.Dv SIGTTOU ,
|
|
|
|
the
|
1996-04-08 04:18:31 +00:00
|
|
|
.Xr write 2
|
1994-05-30 19:09:18 +00:00
|
|
|
returns -1 with
|
|
|
|
errno set to
|
2000-11-22 16:11:48 +00:00
|
|
|
.Er EIO
|
1994-05-30 19:09:18 +00:00
|
|
|
and no signal is sent.
|
|
|
|
.Pp
|
|
|
|
Certain calls that set terminal parameters are treated in the same
|
|
|
|
fashion as write, except that
|
|
|
|
.Dv TOSTOP
|
|
|
|
is ignored; that is, the effect is
|
|
|
|
identical to that of terminal writes when
|
|
|
|
.Dv TOSTOP
|
|
|
|
is set.
|
|
|
|
.Ss Input Processing and Reading Data
|
|
|
|
A terminal device associated with a terminal device file may operate in
|
|
|
|
full-duplex mode, so that data may arrive even while output is occurring.
|
|
|
|
Each terminal device file has associated with it an input queue, into
|
|
|
|
which incoming data is stored by the system before being read by a
|
2004-07-03 18:29:24 +00:00
|
|
|
process.
|
|
|
|
The system imposes a limit,
|
1994-05-30 19:09:18 +00:00
|
|
|
.Pf \&{ Dv MAX_INPUT Ns \&} ,
|
|
|
|
on the number of
|
2003-06-28 23:53:39 +00:00
|
|
|
bytes that may be stored in the input queue.
|
|
|
|
The behavior of the system
|
1994-05-30 19:09:18 +00:00
|
|
|
when this limit is exceeded depends on the setting of the
|
|
|
|
.Dv IMAXBEL
|
|
|
|
flag in the termios
|
|
|
|
.Fa c_iflag .
|
|
|
|
If this flag is set, the terminal
|
|
|
|
is sent an
|
|
|
|
.Tn ASCII
|
|
|
|
.Dv BEL
|
|
|
|
character each time a character is received
|
2003-06-28 23:53:39 +00:00
|
|
|
while the input queue is full.
|
|
|
|
Otherwise, the input queue is flushed upon receiving the character.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Pp
|
|
|
|
Two general kinds of input processing are available, determined by
|
|
|
|
whether the terminal device file is in canonical mode or noncanonical
|
2000-03-01 14:50:24 +00:00
|
|
|
mode.
|
|
|
|
Additionally,
|
1994-05-30 19:09:18 +00:00
|
|
|
input characters are processed according to the
|
|
|
|
.Fa c_iflag
|
|
|
|
and
|
|
|
|
.Fa c_lflag
|
2004-07-03 18:29:24 +00:00
|
|
|
fields.
|
|
|
|
Such processing can include echoing, which
|
1994-05-30 19:09:18 +00:00
|
|
|
in general means transmitting input characters immediately back to the
|
2003-06-28 23:53:39 +00:00
|
|
|
terminal when they are received from the terminal.
|
|
|
|
This is useful for terminals that can operate in full-duplex mode.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Pp
|
|
|
|
The manner in which data is provided to a process reading from a terminal
|
|
|
|
device file is dependent on whether the terminal device file is in
|
|
|
|
canonical or noncanonical mode.
|
|
|
|
.Pp
|
|
|
|
Another dependency is whether the
|
|
|
|
.Dv O_NONBLOCK
|
|
|
|
flag is set by
|
1996-04-08 04:18:31 +00:00
|
|
|
.Xr open 2
|
1994-05-30 19:09:18 +00:00
|
|
|
or
|
1996-04-08 04:18:31 +00:00
|
|
|
.Xr fcntl 2 .
|
1994-05-30 19:09:18 +00:00
|
|
|
If the
|
|
|
|
.Dv O_NONBLOCK
|
|
|
|
flag is clear, then the read request is
|
2003-06-28 23:53:39 +00:00
|
|
|
blocked until data is available or a signal has been received.
|
|
|
|
If the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv O_NONBLOCK
|
|
|
|
flag is set, then the read request is completed, without
|
|
|
|
blocking, in one of three ways:
|
|
|
|
.Bl -enum -offset indent
|
|
|
|
.It
|
|
|
|
If there is enough data available to satisfy the entire request,
|
|
|
|
and the read completes successfully the number of
|
|
|
|
bytes read is returned.
|
|
|
|
.It
|
|
|
|
If there is not enough data available to satisfy the entire
|
|
|
|
request, and the read completes successfully, having read as
|
|
|
|
much data as possible, the number of bytes read is returned.
|
|
|
|
.It
|
|
|
|
If there is no data available, the read returns -1, with
|
|
|
|
errno set to
|
|
|
|
.Er EAGAIN .
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
When data is available depends on whether the input processing mode is
|
|
|
|
canonical or noncanonical.
|
|
|
|
.Ss Canonical Mode Input Processing
|
|
|
|
In canonical mode input processing, terminal input is processed in units
|
2004-07-03 18:29:24 +00:00
|
|
|
of lines.
|
|
|
|
A line is delimited by a newline
|
1994-05-30 19:09:18 +00:00
|
|
|
.Ql \&\en
|
|
|
|
character, an end-of-file
|
|
|
|
.Pq Dv EOF
|
|
|
|
character, or an end-of-line
|
|
|
|
.Pq Dv EOL
|
2004-07-03 18:29:24 +00:00
|
|
|
character.
|
|
|
|
See the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Sx "Special Characters"
|
|
|
|
section for
|
|
|
|
more information on
|
|
|
|
.Dv EOF
|
|
|
|
and
|
|
|
|
.Dv EOL .
|
|
|
|
This means that a read request will
|
|
|
|
not return until an entire line has been typed, or a signal has been
|
2003-06-28 23:53:39 +00:00
|
|
|
received.
|
|
|
|
Also, no matter how many bytes are requested in the read call,
|
|
|
|
at most one line is returned.
|
|
|
|
It is not, however, necessary to
|
1994-05-30 19:09:18 +00:00
|
|
|
read a whole line at once; any number of bytes, even one, may be
|
|
|
|
requested in a read without losing information.
|
|
|
|
.Pp
|
|
|
|
.Pf \&{ Dv MAX_CANON Ns \&}
|
|
|
|
is a limit on the
|
|
|
|
number of bytes in a line.
|
|
|
|
The behavior of the system when this limit is
|
|
|
|
exceeded is the same as when the input queue limit
|
|
|
|
.Pf \&{ Dv MAX_INPUT Ns \&} ,
|
|
|
|
is exceeded.
|
|
|
|
.Pp
|
|
|
|
Erase and kill processing occur when either of two special characters,
|
|
|
|
the
|
|
|
|
.Dv ERASE
|
|
|
|
and
|
|
|
|
.Dv KILL
|
|
|
|
characters (see the
|
|
|
|
.Sx "Special Characters section" ) ,
|
|
|
|
is received.
|
|
|
|
This processing affects data in the input queue that has not yet been
|
|
|
|
delimited by a newline
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv NL ,
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv EOF ,
|
|
|
|
or
|
|
|
|
.Dv EOL
|
2004-07-03 18:29:24 +00:00
|
|
|
character.
|
|
|
|
This un-delimited
|
2003-06-28 23:53:39 +00:00
|
|
|
data makes up the current line.
|
|
|
|
The
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ERASE
|
|
|
|
character deletes the last
|
2003-06-28 23:53:39 +00:00
|
|
|
character in the current line, if there is any.
|
|
|
|
The
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv KILL
|
|
|
|
character
|
2003-06-28 23:53:39 +00:00
|
|
|
deletes all data in the current line, if there is any.
|
|
|
|
The
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ERASE
|
|
|
|
and
|
|
|
|
.Dv KILL
|
|
|
|
characters have no effect if there is no data in the current line.
|
|
|
|
The
|
|
|
|
.Dv ERASE
|
|
|
|
and
|
|
|
|
.Dv KILL
|
|
|
|
characters themselves are not placed in the input
|
|
|
|
queue.
|
|
|
|
.Ss Noncanonical Mode Input Processing
|
|
|
|
In noncanonical mode input processing, input bytes are not assembled into
|
2003-06-28 23:53:39 +00:00
|
|
|
lines, and erase and kill processing does not occur.
|
|
|
|
The values of the
|
1997-03-14 05:01:14 +00:00
|
|
|
.Dv VMIN
|
1994-05-30 19:09:18 +00:00
|
|
|
and
|
1997-03-14 05:01:14 +00:00
|
|
|
.Dv VTIME
|
1994-05-30 19:09:18 +00:00
|
|
|
members of the
|
|
|
|
.Fa c_cc
|
|
|
|
array are used to determine how to
|
|
|
|
process the bytes received.
|
|
|
|
.Pp
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
represents the minimum number of bytes that should be received when
|
|
|
|
the
|
1996-04-08 04:18:31 +00:00
|
|
|
.Xr read 2
|
1994-05-30 19:09:18 +00:00
|
|
|
function successfully returns.
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
is a timer of 0.1 second
|
|
|
|
granularity that is used to time out bursty and short term data
|
2004-07-03 18:29:24 +00:00
|
|
|
transmissions.
|
|
|
|
If
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
is greater than
|
|
|
|
.Dv \&{ Dv MAX_INPUT Ns \&} ,
|
|
|
|
the response to the
|
2003-06-28 23:53:39 +00:00
|
|
|
request is undefined.
|
|
|
|
The four possible values for
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
and
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
and
|
|
|
|
their interactions are described below.
|
1997-03-18 07:17:22 +00:00
|
|
|
.Ss "Case A: MIN > 0, TIME > 0"
|
1994-05-30 19:09:18 +00:00
|
|
|
In this case
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
serves as an inter-byte timer and is activated after
|
2003-06-28 23:53:39 +00:00
|
|
|
the first byte is received.
|
|
|
|
Since it is an inter-byte timer, it is reset
|
|
|
|
after a byte is received.
|
|
|
|
The interaction between
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
and
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
is as
|
2004-07-03 18:29:24 +00:00
|
|
|
follows: as soon as one byte is received, the inter-byte timer is
|
|
|
|
started.
|
|
|
|
If
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
bytes are received before the inter-byte timer expires
|
|
|
|
(remember that the timer is reset upon receipt of each byte), the read is
|
2003-06-28 23:53:39 +00:00
|
|
|
satisfied.
|
|
|
|
If the timer expires before
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
bytes are received, the
|
2003-06-28 23:53:39 +00:00
|
|
|
characters received to that point are returned to the user.
|
|
|
|
Note that if
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
expires at least one byte is returned because the timer would
|
2003-06-28 23:53:39 +00:00
|
|
|
not have been enabled unless a byte was received.
|
|
|
|
In this case
|
1997-03-18 07:17:22 +00:00
|
|
|
.Pf \&( Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
> 0,
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
> 0) the read blocks until the
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
and
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
mechanisms are
|
2003-06-28 23:53:39 +00:00
|
|
|
activated by the receipt of the first byte, or a signal is received.
|
|
|
|
If data is in the buffer at the time of the
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn read ,
|
|
|
|
the result is as
|
|
|
|
if data had been received immediately after the
|
|
|
|
.Fn read .
|
1997-03-18 07:17:22 +00:00
|
|
|
.Ss "Case B: MIN > 0, TIME = 0"
|
1994-05-30 19:09:18 +00:00
|
|
|
In this case, since the value of
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
is zero, the timer plays no role
|
|
|
|
and only
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
2003-06-28 23:53:39 +00:00
|
|
|
is significant.
|
|
|
|
A pending read is not satisfied until
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
bytes are received (i.e., the pending read blocks until
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
bytes
|
2003-06-28 23:53:39 +00:00
|
|
|
are received), or a signal is received.
|
|
|
|
A program that uses this case to read record-based terminal
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv I/O
|
|
|
|
may block indefinitely in the read
|
|
|
|
operation.
|
1997-03-18 07:17:22 +00:00
|
|
|
.Ss "Case C: MIN = 0, TIME > 0"
|
1994-05-30 19:09:18 +00:00
|
|
|
In this case, since
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
= 0,
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
1994-05-30 19:09:18 +00:00
|
|
|
no longer represents an inter-byte
|
2003-06-28 23:53:39 +00:00
|
|
|
timer.
|
|
|
|
It now serves as a read timer that is activated as soon as the
|
|
|
|
read function is processed.
|
|
|
|
A read is satisfied as soon as a single
|
|
|
|
byte is received or the read timer expires.
|
|
|
|
Note that in this case if the timer expires, no bytes are returned.
|
|
|
|
If the timer does not
|
1994-05-30 19:09:18 +00:00
|
|
|
expire, the only way the read can be satisfied is if a byte is received.
|
|
|
|
In this case the read will not block indefinitely waiting for a byte; if
|
|
|
|
no byte is received within
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME Ns *0.1
|
1994-05-30 19:09:18 +00:00
|
|
|
seconds after the read is initiated,
|
2003-06-28 23:53:39 +00:00
|
|
|
the read returns a value of zero, having read no data.
|
|
|
|
If data is
|
1994-05-30 19:09:18 +00:00
|
|
|
in the buffer at the time of the read, the timer is started as if
|
|
|
|
data had been received immediately after the read.
|
1997-03-18 07:17:22 +00:00
|
|
|
.Ss Case D: MIN = 0, TIME = 0
|
1994-05-30 19:09:18 +00:00
|
|
|
The minimum of either the number of bytes requested or the number of
|
|
|
|
bytes currently available is returned without waiting for more
|
2003-06-28 23:53:39 +00:00
|
|
|
bytes to be input.
|
|
|
|
If no characters are available, read returns a
|
1994-05-30 19:09:18 +00:00
|
|
|
value of zero, having read no data.
|
|
|
|
.Ss Writing Data and Output Processing
|
|
|
|
When a process writes one or more bytes to a terminal device file, they
|
|
|
|
are processed according to the
|
|
|
|
.Fa c_oflag
|
|
|
|
field (see the
|
|
|
|
.Sx "Output Modes
|
2004-07-03 18:29:24 +00:00
|
|
|
section).
|
|
|
|
The
|
1994-05-30 19:09:18 +00:00
|
|
|
implementation may provide a buffering mechanism; as such, when a call to
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn write
|
|
|
|
completes, all of the bytes written have been scheduled for
|
1994-05-30 19:09:18 +00:00
|
|
|
transmission to the device, but the transmission will not necessarily
|
|
|
|
have been completed.
|
|
|
|
.\" See also .Sx "6.4.2" for the effects of
|
|
|
|
.\" .Dv O_NONBLOCK
|
|
|
|
.\" on write.
|
|
|
|
.Ss Special Characters
|
|
|
|
Certain characters have special functions on input or output or both.
|
|
|
|
These functions are summarized as follows:
|
|
|
|
.Bl -tag -width indent
|
|
|
|
.It Dv INTR
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ISIG
|
|
|
|
flag (see the
|
|
|
|
.Sx "Local Modes"
|
2003-06-28 23:53:39 +00:00
|
|
|
section) is enabled.
|
|
|
|
Generates a
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv SIGINT
|
|
|
|
signal which is sent to all processes in the foreground
|
|
|
|
process group for which the terminal is the controlling
|
2004-07-03 18:29:24 +00:00
|
|
|
terminal.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ISIG
|
|
|
|
is set, the
|
|
|
|
.Dv INTR
|
|
|
|
character is
|
|
|
|
discarded when processed.
|
|
|
|
.It Dv QUIT
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ISIG
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is enabled.
|
|
|
|
Generates a
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv SIGQUIT
|
|
|
|
signal which is
|
|
|
|
sent to all processes in the foreground process group
|
2003-06-28 23:53:39 +00:00
|
|
|
for which the terminal is the controlling terminal.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ISIG
|
|
|
|
is set, the
|
|
|
|
.Dv QUIT
|
|
|
|
character is discarded when
|
|
|
|
processed.
|
|
|
|
.It Dv ERASE
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Erases the last character in the
|
1994-05-30 19:09:18 +00:00
|
|
|
current line; see
|
|
|
|
.Sx "Canonical Mode Input Processing" .
|
|
|
|
It does not erase beyond
|
|
|
|
the start of a line, as delimited by an
|
|
|
|
.Dv NL ,
|
|
|
|
.Dv EOF ,
|
|
|
|
or
|
|
|
|
.Dv EOL
|
2003-06-28 23:53:39 +00:00
|
|
|
character.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ICANON
|
|
|
|
is set, the
|
|
|
|
.Dv ERASE
|
|
|
|
character is
|
|
|
|
discarded when processed.
|
|
|
|
.It Dv KILL
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Deletes the entire line, as
|
1994-05-30 19:09:18 +00:00
|
|
|
delimited by a
|
|
|
|
.Dv NL ,
|
|
|
|
.Dv EOF ,
|
|
|
|
or
|
|
|
|
.Dv EOL
|
2003-06-28 23:53:39 +00:00
|
|
|
character.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ICANON
|
|
|
|
is set, the
|
|
|
|
.Dv KILL
|
|
|
|
character is discarded when processed.
|
|
|
|
.It Dv EOF
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
When received, all the bytes
|
1994-05-30 19:09:18 +00:00
|
|
|
waiting to be read are immediately passed to the
|
|
|
|
process, without waiting for a newline, and the
|
|
|
|
.Dv EOF
|
2003-06-28 23:53:39 +00:00
|
|
|
is discarded.
|
|
|
|
Thus, if there are no bytes waiting (that is, the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv EOF
|
|
|
|
occurred at the beginning of a line), a byte
|
2001-07-14 19:41:16 +00:00
|
|
|
count of zero is returned from the
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn read ,
|
2003-06-28 23:53:39 +00:00
|
|
|
representing an end-of-file indication.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ICANON
|
|
|
|
is
|
|
|
|
set, the
|
|
|
|
.Dv EOF
|
|
|
|
character is discarded when processed.
|
2000-09-18 23:00:15 +00:00
|
|
|
.It Dv NL
|
1994-05-30 19:09:18 +00:00
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
It is the line delimiter
|
1994-05-30 19:09:18 +00:00
|
|
|
.Ql \&\en .
|
|
|
|
.It Dv EOL
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Is an additional line delimiter, like
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv NL .
|
|
|
|
.It Dv SUSP
|
|
|
|
If the
|
|
|
|
.Dv ISIG
|
|
|
|
flag is enabled, receipt of the
|
|
|
|
.Dv SUSP
|
|
|
|
character causes a
|
|
|
|
.Dv SIGTSTP
|
|
|
|
signal to be sent to all processes in the
|
|
|
|
foreground process group for which the terminal is the
|
|
|
|
controlling terminal, and the
|
|
|
|
.Dv SUSP
|
|
|
|
character is
|
|
|
|
discarded when processed.
|
|
|
|
.It Dv STOP
|
|
|
|
Special character on both input and output and is
|
|
|
|
recognized if the
|
|
|
|
.Dv IXON
|
|
|
|
(output control) or
|
|
|
|
.Dv IXOFF
|
|
|
|
(input
|
2003-06-28 23:53:39 +00:00
|
|
|
control) flag is set.
|
|
|
|
Can be used to temporarily suspend output.
|
|
|
|
It is useful with fast terminals to
|
1994-05-30 19:09:18 +00:00
|
|
|
prevent output from disappearing before it can be read.
|
|
|
|
If
|
|
|
|
.Dv IXON
|
|
|
|
is set, the
|
|
|
|
.Dv STOP
|
|
|
|
character is discarded when
|
|
|
|
processed.
|
|
|
|
.It Dv START
|
|
|
|
Special character on both input and output and is
|
|
|
|
recognized if the
|
|
|
|
.Dv IXON
|
|
|
|
(output control) or
|
|
|
|
.Dv IXOFF
|
|
|
|
(input
|
2003-06-28 23:53:39 +00:00
|
|
|
control) flag is set.
|
|
|
|
Can be used to resume output that has been suspended by a
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv STOP
|
2004-07-03 18:29:24 +00:00
|
|
|
character.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IXON
|
|
|
|
is set, the
|
|
|
|
.Dv START
|
|
|
|
character is discarded when processed.
|
2000-09-18 23:00:15 +00:00
|
|
|
.It Dv CR
|
1994-05-30 19:09:18 +00:00
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
|
|
|
flag is set; it is the
|
|
|
|
.Ql \&\er ,
|
|
|
|
as denoted in the
|
|
|
|
.Tn \&C
|
2003-06-28 23:53:39 +00:00
|
|
|
Standard {2}.
|
|
|
|
When
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ICANON
|
|
|
|
and
|
|
|
|
.Dv ICRNL
|
|
|
|
are set and
|
|
|
|
.Dv IGNCR
|
|
|
|
is not set, this character is translated into a
|
|
|
|
.Dv NL ,
|
|
|
|
and
|
|
|
|
has the same effect as a
|
|
|
|
.Dv NL
|
|
|
|
character.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
The following special characters are extensions defined by this
|
2001-02-26 15:57:37 +00:00
|
|
|
system and are not a part of
|
|
|
|
.St -p1003.1
|
|
|
|
termios.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Bl -tag -width indent
|
|
|
|
.It Dv EOL2
|
|
|
|
Secondary
|
|
|
|
.Dv EOL
|
2004-07-03 18:29:24 +00:00
|
|
|
character.
|
|
|
|
Same function as
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv EOL .
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv WERASE
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Erases the last word in the current line according to one of two algorithms.
|
|
|
|
If the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ALTWERASE
|
|
|
|
flag is not set, first any preceding whitespace is
|
|
|
|
erased, and then the maximal sequence of non-whitespace
|
2003-06-28 23:53:39 +00:00
|
|
|
characters.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ALTWERASE
|
|
|
|
is set, first any preceding
|
|
|
|
whitespace is erased, and then the maximal sequence
|
|
|
|
of alphabetic/underscores or non alphabetic/underscores.
|
|
|
|
As a special case in this second algorithm, the first previous
|
|
|
|
non-whitespace character is skipped in determining
|
|
|
|
whether the preceding word is a sequence of
|
2003-06-28 23:53:39 +00:00
|
|
|
alphabetic/underscores.
|
|
|
|
This sounds confusing but turns out to be quite practical.
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv REPRINT
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Causes the current input edit line to be retyped.
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv DSUSP
|
|
|
|
Has similar actions to the
|
|
|
|
.Dv SUSP
|
|
|
|
character, except that
|
|
|
|
the
|
|
|
|
.Dv SIGTSTP
|
|
|
|
signal is delivered when one of the processes
|
1996-04-08 04:18:31 +00:00
|
|
|
in the foreground process group issues a
|
|
|
|
.Fn read
|
|
|
|
to the
|
1994-05-30 19:09:18 +00:00
|
|
|
controlling terminal.
|
|
|
|
.It Dv LNEXT
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv IEXTEN
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Receipt of this character causes the next character to be taken literally.
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv DISCARD
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv IEXTEN
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Receipt of this character toggles the flushing of terminal output.
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv STATUS
|
|
|
|
Special character on input and is recognized if the
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
flag is set.
|
|
|
|
Receipt of this character causes a
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv SIGINFO
|
|
|
|
signal to be sent to the foreground process group of the
|
2003-06-28 23:53:39 +00:00
|
|
|
terminal.
|
|
|
|
Also, if the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv NOKERNINFO
|
|
|
|
flag is not set, it
|
|
|
|
causes the kernel to write a status message to the terminal
|
|
|
|
that displays the current load average, the name of the
|
|
|
|
command in the foreground, its process ID, the symbolic
|
|
|
|
wait channel, the number of user and system seconds used,
|
|
|
|
the percentage of cpu the process is getting, and the resident
|
|
|
|
set size of the process.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
The
|
|
|
|
.Dv NL
|
|
|
|
and
|
|
|
|
.Dv CR
|
|
|
|
characters cannot be changed.
|
|
|
|
The values for all the remaining characters can be set and are
|
|
|
|
described later in the document under
|
|
|
|
Special Control Characters.
|
|
|
|
.Pp
|
|
|
|
Special
|
|
|
|
character functions associated with changeable special control characters
|
|
|
|
can be disabled individually by setting their value to
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv {_POSIX_VDISABLE} ;
|
1994-05-30 19:09:18 +00:00
|
|
|
see
|
|
|
|
.Sx "Special Control Characters" .
|
|
|
|
.Pp
|
|
|
|
If two or more special characters have the same value, the function
|
|
|
|
performed when that character is received is undefined.
|
|
|
|
.Ss Modem Disconnect
|
|
|
|
If a modem disconnect is detected by the terminal interface for a
|
|
|
|
controlling terminal, and if
|
|
|
|
.Dv CLOCAL
|
|
|
|
is not set in the
|
|
|
|
.Fa c_cflag
|
|
|
|
field for
|
|
|
|
the terminal, the
|
|
|
|
.Dv SIGHUP
|
|
|
|
signal is sent to the controlling
|
2003-06-28 23:53:39 +00:00
|
|
|
process associated with the terminal.
|
|
|
|
Unless other arrangements have
|
1994-05-30 19:09:18 +00:00
|
|
|
been made, this causes the controlling process to terminate.
|
1996-04-08 04:18:31 +00:00
|
|
|
Any subsequent call to the
|
|
|
|
.Fn read
|
|
|
|
function returns the value zero,
|
2003-06-28 23:53:39 +00:00
|
|
|
indicating end of file.
|
|
|
|
Thus, processes that read a terminal
|
1994-05-30 19:09:18 +00:00
|
|
|
file and test for end-of-file can terminate appropriately after a
|
|
|
|
disconnect.
|
|
|
|
.\" If the
|
|
|
|
.\" .Er EIO
|
|
|
|
.\" condition specified in 6.1.1.4 that applies
|
|
|
|
.\" when the implementation supports job control also exists, it is
|
|
|
|
.\" unspecified whether the
|
|
|
|
.\" .Dv EOF
|
|
|
|
.\" condition or the
|
|
|
|
.\" .Pf [ Dv EIO
|
|
|
|
.\" ] is returned.
|
|
|
|
Any
|
1996-04-08 04:18:31 +00:00
|
|
|
subsequent
|
|
|
|
.Fn write
|
|
|
|
to the terminal device returns -1, with
|
1994-05-30 19:09:18 +00:00
|
|
|
.Va errno
|
|
|
|
set to
|
|
|
|
.Er EIO ,
|
|
|
|
until the device is closed.
|
|
|
|
.Sh General Terminal Interface
|
|
|
|
.Ss Closing a Terminal Device File
|
|
|
|
The last process to close a terminal device file causes any output
|
2003-06-28 23:53:39 +00:00
|
|
|
to be sent to the device and any input to be discarded.
|
|
|
|
Then, if
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv HUPCL
|
|
|
|
is set in the control modes, and the communications port supports a
|
|
|
|
disconnect function, the terminal device performs a disconnect.
|
|
|
|
.Ss Parameters That Can Be Set
|
|
|
|
Routines that need to control certain terminal
|
|
|
|
.Tn I/O
|
|
|
|
characteristics
|
|
|
|
do so by using the termios structure as defined in the header
|
2003-09-08 19:57:22 +00:00
|
|
|
.In termios.h .
|
1994-05-30 19:09:18 +00:00
|
|
|
This structure contains minimally four scalar elements of bit flags
|
2003-06-28 23:53:39 +00:00
|
|
|
and one array of special characters.
|
|
|
|
The scalar flag elements are named:
|
1994-05-30 19:09:18 +00:00
|
|
|
.Fa c_iflag ,
|
|
|
|
.Fa c_oflag ,
|
|
|
|
.Fa c_cflag ,
|
|
|
|
and
|
|
|
|
.Fa c_lflag .
|
|
|
|
The character array is named
|
|
|
|
.Fa c_cc ,
|
|
|
|
and its maximum index is
|
|
|
|
.Dv NCCS .
|
|
|
|
.Ss Input Modes
|
|
|
|
Values of the
|
|
|
|
.Fa c_iflag
|
|
|
|
field describe the basic
|
|
|
|
terminal input control, and are composed of
|
|
|
|
following masks:
|
|
|
|
.Pp
|
|
|
|
.Bl -tag -width IMAXBEL -offset indent -compact
|
|
|
|
.It Dv IGNBRK
|
|
|
|
/* ignore BREAK condition */
|
|
|
|
.It Dv BRKINT
|
|
|
|
/* map BREAK to SIGINTR */
|
|
|
|
.It Dv IGNPAR
|
|
|
|
/* ignore (discard) parity errors */
|
|
|
|
.It Dv PARMRK
|
|
|
|
/* mark parity and framing errors */
|
|
|
|
.It Dv INPCK
|
|
|
|
/* enable checking of parity errors */
|
|
|
|
.It Dv ISTRIP
|
|
|
|
/* strip 8th bit off chars */
|
|
|
|
.It Dv INLCR
|
|
|
|
/* map NL into CR */
|
|
|
|
.It Dv IGNCR
|
|
|
|
/* ignore CR */
|
|
|
|
.It Dv ICRNL
|
|
|
|
/* map CR to NL (ala CRMOD) */
|
|
|
|
.It Dv IXON
|
|
|
|
/* enable output flow control */
|
|
|
|
.It Dv IXOFF
|
|
|
|
/* enable input flow control */
|
|
|
|
.It Dv IXANY
|
|
|
|
/* any char will restart after stop */
|
|
|
|
.It Dv IMAXBEL
|
|
|
|
/* ring bell on input queue full */
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
In the context of asynchronous serial data transmission, a break
|
|
|
|
condition is defined as a sequence of zero-valued bits that continues for
|
2003-06-28 23:53:39 +00:00
|
|
|
more than the time to send one byte.
|
|
|
|
The entire sequence of zero-valued
|
1994-05-30 19:09:18 +00:00
|
|
|
bits is interpreted as a single break condition, even if it continues for
|
2003-06-28 23:53:39 +00:00
|
|
|
a time equivalent to more than one byte.
|
|
|
|
In contexts other than
|
1994-05-30 19:09:18 +00:00
|
|
|
asynchronous serial data transmission the definition of a break condition
|
|
|
|
is implementation defined.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv IGNBRK
|
|
|
|
is set, a break condition detected on input is ignored, that
|
2003-06-28 23:53:39 +00:00
|
|
|
is, not put on the input queue and therefore not read by any process.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IGNBRK
|
|
|
|
is not set and
|
|
|
|
.Dv BRKINT
|
|
|
|
is set, the break condition flushes the
|
|
|
|
input and output queues and if the terminal is the controlling terminal
|
|
|
|
of a foreground process group, the break condition generates a
|
|
|
|
single
|
|
|
|
.Dv SIGINT
|
2003-06-28 23:53:39 +00:00
|
|
|
signal to that foreground process group.
|
|
|
|
If neither
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IGNBRK
|
|
|
|
nor
|
|
|
|
.Dv BRKINT
|
|
|
|
is set, a break condition is read as a single
|
|
|
|
.Ql \&\e0 ,
|
|
|
|
or if
|
|
|
|
.Dv PARMRK
|
|
|
|
is set, as
|
|
|
|
.Ql \&\e377 ,
|
|
|
|
.Ql \&\e0 ,
|
|
|
|
.Ql \&\e0 .
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv IGNPAR
|
|
|
|
is set, a byte with a framing or parity error (other than
|
|
|
|
break) is ignored.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv PARMRK
|
|
|
|
is set, and
|
|
|
|
.Dv IGNPAR
|
|
|
|
is not set, a byte with a framing or parity
|
|
|
|
error (other than break) is given to the application as the
|
|
|
|
three-character sequence
|
|
|
|
.Ql \&\e377 ,
|
|
|
|
.Ql \&\e0 ,
|
|
|
|
X, where
|
|
|
|
.Ql \&\e377 ,
|
|
|
|
.Ql \&\e0
|
|
|
|
is a two-character
|
|
|
|
flag preceding each sequence and X is the data of the character received
|
2004-07-03 18:29:24 +00:00
|
|
|
in error.
|
|
|
|
To avoid ambiguity in this case, if
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ISTRIP
|
|
|
|
is not set, a valid
|
|
|
|
character of
|
|
|
|
.Ql \&\e377
|
|
|
|
is given to the application as
|
|
|
|
.Ql \&\e377 ,
|
|
|
|
.Ql \&\e377 .
|
|
|
|
If
|
|
|
|
neither
|
|
|
|
.Dv PARMRK
|
|
|
|
nor
|
|
|
|
.Dv IGNPAR
|
|
|
|
is set, a framing or parity error (other than
|
|
|
|
break) is given to the application as a single character
|
|
|
|
.Ql \&\e0 .
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv INPCK
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, input parity checking is enabled.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv INPCK
|
|
|
|
is not set,
|
|
|
|
input parity checking is disabled, allowing output parity generation
|
2003-06-28 23:53:39 +00:00
|
|
|
without input parity errors.
|
|
|
|
Note that whether input parity checking is
|
1994-05-30 19:09:18 +00:00
|
|
|
enabled or disabled is independent of whether parity detection is enabled
|
|
|
|
or disabled (see
|
|
|
|
.Sx "Control Modes" ) .
|
|
|
|
If parity detection is enabled but input
|
|
|
|
parity checking is disabled, the hardware to which the terminal is
|
|
|
|
connected recognizes the parity bit, but the terminal special file
|
|
|
|
does not check whether this bit is set correctly or not.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ISTRIP
|
|
|
|
is set, valid input bytes are first stripped to seven bits,
|
|
|
|
otherwise all eight bits are processed.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv INLCR
|
|
|
|
is set, a received
|
|
|
|
.Dv NL
|
|
|
|
character is translated into a
|
|
|
|
.Dv CR
|
2004-07-03 18:29:24 +00:00
|
|
|
character.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IGNCR
|
|
|
|
is set, a received
|
|
|
|
.Dv CR
|
|
|
|
character is ignored (not
|
2004-07-03 18:29:24 +00:00
|
|
|
read).
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IGNCR
|
|
|
|
is not set and
|
|
|
|
.Dv ICRNL
|
|
|
|
is set, a received
|
|
|
|
.Dv CR
|
|
|
|
character is
|
|
|
|
translated into a
|
|
|
|
.Dv NL
|
|
|
|
character.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv IXON
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, start/stop output control is enabled.
|
|
|
|
A received
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv STOP
|
|
|
|
character suspends output and a received
|
|
|
|
.Dv START
|
|
|
|
character
|
2000-03-01 14:50:24 +00:00
|
|
|
restarts output.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IXANY
|
|
|
|
is also set, then any character may
|
2000-03-01 14:50:24 +00:00
|
|
|
restart output.
|
|
|
|
When
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IXON
|
|
|
|
is set,
|
|
|
|
.Dv START
|
|
|
|
and
|
|
|
|
.Dv STOP
|
|
|
|
characters are not
|
2003-06-28 23:53:39 +00:00
|
|
|
read, but merely perform flow control functions.
|
|
|
|
When
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IXON
|
|
|
|
is not set,
|
|
|
|
the
|
|
|
|
.Dv START
|
|
|
|
and
|
|
|
|
.Dv STOP
|
|
|
|
characters are read.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv IXOFF
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, start/stop input control is enabled.
|
|
|
|
The system shall transmit one or more
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv STOP
|
|
|
|
characters, which are intended to cause the
|
|
|
|
terminal device to stop transmitting data, as needed to prevent the input
|
|
|
|
queue from overflowing and causing the undefined behavior described in
|
|
|
|
.Sx "Input Processing and Reading Data" ,
|
|
|
|
and shall transmit one or more
|
|
|
|
.Dv START
|
|
|
|
characters, which are
|
|
|
|
intended to cause the terminal device to resume transmitting data, as
|
|
|
|
soon as the device can continue transmitting data without risk of
|
2003-06-28 23:53:39 +00:00
|
|
|
overflowing the input queue.
|
|
|
|
The precise conditions under which
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv STOP
|
|
|
|
and
|
|
|
|
START
|
|
|
|
characters are transmitted are implementation defined.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv IMAXBEL
|
|
|
|
is set and the input queue is full, subsequent input shall cause an
|
|
|
|
.Tn ASCII
|
|
|
|
.Dv BEL
|
1999-02-12 02:12:08 +00:00
|
|
|
character to be transmitted to
|
1994-05-30 19:09:18 +00:00
|
|
|
the output queue.
|
|
|
|
.Pp
|
2001-07-14 19:41:16 +00:00
|
|
|
The initial input control value after
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn open
|
|
|
|
is implementation defined.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Ss Output Modes
|
|
|
|
Values of the
|
|
|
|
.Fa c_oflag
|
|
|
|
field describe the basic terminal output control,
|
|
|
|
and are composed of the following masks:
|
|
|
|
.Pp
|
|
|
|
.Bl -tag -width OXTABS -offset indent -compact
|
|
|
|
.It Dv OPOST
|
|
|
|
/* enable following output processing */
|
|
|
|
.It Dv ONLCR
|
|
|
|
/* map NL to CR-NL (ala
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv CRMOD )
|
1994-05-30 19:09:18 +00:00
|
|
|
*/
|
2001-03-04 06:04:50 +00:00
|
|
|
.It Dv OCRNL
|
|
|
|
/* map CR to NL */
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv OXTABS
|
|
|
|
/* expand tabs to spaces */
|
|
|
|
.It Dv ONOEOT
|
|
|
|
/* discard
|
|
|
|
.Dv EOT Ns 's
|
|
|
|
.Ql \&^D
|
|
|
|
on output) */
|
2001-03-04 06:04:50 +00:00
|
|
|
.It Dv ONOCR
|
|
|
|
/* do not transmit CRs on column 0 */
|
|
|
|
.It Dv ONLRET
|
2002-01-21 12:09:13 +00:00
|
|
|
/* on the terminal NL performs the CR function */
|
1994-05-30 19:09:18 +00:00
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv OPOST
|
|
|
|
is set, the remaining flag masks are interpreted as follows;
|
|
|
|
otherwise characters are transmitted without change.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ONLCR
|
|
|
|
is set, newlines are translated to carriage return, linefeeds.
|
|
|
|
.Pp
|
|
|
|
If
|
2001-03-04 06:04:50 +00:00
|
|
|
.Dv OCRNL
|
|
|
|
is set, carriage returns are translated to newlines.
|
|
|
|
.Pp
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv OXTABS
|
|
|
|
is set, tabs are expanded to the appropriate number of
|
|
|
|
spaces (assuming 8 column tab stops).
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ONOEOT
|
|
|
|
is set,
|
|
|
|
.Tn ASCII
|
2000-11-22 13:49:11 +00:00
|
|
|
.Dv EOT Ns 's
|
1994-05-30 19:09:18 +00:00
|
|
|
are discarded on output.
|
2001-03-04 06:04:50 +00:00
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ONOCR
|
|
|
|
is set, no CR character is transmitted when at column 0 (first position).
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ONLRET
|
|
|
|
is set, the NL character is assumed to do the carriage-return function;
|
|
|
|
the column pointer will be set to 0.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Ss Control Modes
|
|
|
|
Values of the
|
|
|
|
.Fa c_cflag
|
|
|
|
field describe the basic
|
|
|
|
terminal hardware control, and are composed of the
|
|
|
|
following masks.
|
|
|
|
Not all values
|
|
|
|
specified are supported by all hardware.
|
|
|
|
.Pp
|
|
|
|
.Bl -tag -width CRTSXIFLOW -offset indent -compact
|
|
|
|
.It Dv CSIZE
|
|
|
|
/* character size mask */
|
|
|
|
.It Dv CS5
|
|
|
|
/* 5 bits (pseudo) */
|
|
|
|
.It Dv CS6
|
|
|
|
/* 6 bits */
|
|
|
|
.It Dv CS7
|
|
|
|
/* 7 bits */
|
|
|
|
.It Dv CS8
|
|
|
|
/* 8 bits */
|
|
|
|
.It Dv CSTOPB
|
|
|
|
/* send 2 stop bits */
|
|
|
|
.It Dv CREAD
|
|
|
|
/* enable receiver */
|
|
|
|
.It Dv PARENB
|
|
|
|
/* parity enable */
|
|
|
|
.It Dv PARODD
|
|
|
|
/* odd parity, else even */
|
|
|
|
.It Dv HUPCL
|
|
|
|
/* hang up on last close */
|
|
|
|
.It Dv CLOCAL
|
|
|
|
/* ignore modem status lines */
|
|
|
|
.It Dv CCTS_OFLOW
|
|
|
|
/*
|
|
|
|
.Dv CTS
|
|
|
|
flow control of output */
|
|
|
|
.It Dv CRTSCTS
|
|
|
|
/* same as
|
|
|
|
.Dv CCTS_OFLOW
|
|
|
|
*/
|
|
|
|
.It Dv CRTS_IFLOW
|
|
|
|
/* RTS flow control of input */
|
|
|
|
.It Dv MDMBUF
|
|
|
|
/* flow control output via Carrier */
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
The
|
|
|
|
.Dv CSIZE
|
|
|
|
bits specify the byte size in bits for both transmission and
|
2003-06-28 23:53:39 +00:00
|
|
|
reception.
|
|
|
|
The
|
1994-05-30 19:09:18 +00:00
|
|
|
.Fa c_cflag
|
|
|
|
is masked with
|
|
|
|
.Dv CSIZE
|
|
|
|
and compared with the
|
|
|
|
values
|
|
|
|
.Dv CS5 ,
|
|
|
|
.Dv CS6 ,
|
|
|
|
.Dv CS7 ,
|
|
|
|
or
|
|
|
|
.Dv CS8 .
|
2003-06-28 23:53:39 +00:00
|
|
|
This size does not include the parity bit, if any.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv CSTOPB
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, two stop bits are used, otherwise one stop bit.
|
|
|
|
For example, at 110 baud, two stop bits are normally used.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv CREAD
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, the receiver is enabled.
|
|
|
|
Otherwise, no character is received.
|
|
|
|
Not all hardware supports this bit.
|
|
|
|
In fact, this flag is pretty silly and if it were not part of the
|
2000-11-20 18:41:33 +00:00
|
|
|
.Nm
|
1994-05-30 19:09:18 +00:00
|
|
|
specification
|
|
|
|
it would be omitted.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv PARENB
|
|
|
|
is set, parity generation and detection are enabled and a parity
|
2003-06-28 23:53:39 +00:00
|
|
|
bit is added to each character.
|
|
|
|
If parity is enabled,
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv PARODD
|
|
|
|
specifies
|
|
|
|
odd parity if set, otherwise even parity is used.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv HUPCL
|
|
|
|
is set, the modem control lines for the port are lowered
|
|
|
|
when the last process with the port open closes the port or the process
|
2003-06-28 23:53:39 +00:00
|
|
|
terminates.
|
|
|
|
The modem connection is broken.
|
1994-05-30 19:09:18 +00:00
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv CLOCAL
|
|
|
|
is set, a connection does not depend on the state of the modem
|
2003-06-28 23:53:39 +00:00
|
|
|
status lines.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv CLOCAL
|
|
|
|
is clear, the modem status lines are
|
|
|
|
monitored.
|
|
|
|
.Pp
|
2001-07-14 19:41:16 +00:00
|
|
|
Under normal circumstances, a call to the
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn open
|
|
|
|
function waits for
|
2003-06-28 23:53:39 +00:00
|
|
|
the modem connection to complete.
|
|
|
|
However, if the
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv O_NONBLOCK
|
|
|
|
flag is set
|
|
|
|
or if
|
|
|
|
.Dv CLOCAL
|
2001-07-14 19:41:16 +00:00
|
|
|
has been set, the
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn open
|
|
|
|
function returns
|
1994-05-30 19:09:18 +00:00
|
|
|
immediately without waiting for the connection.
|
|
|
|
.Pp
|
|
|
|
The
|
|
|
|
.Dv CCTS_OFLOW
|
|
|
|
.Pf ( Dv CRTSCTS )
|
|
|
|
flag is currently unused.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv MDMBUF
|
|
|
|
is set then output flow control is controlled by the state
|
|
|
|
of Carrier Detect.
|
|
|
|
.Pp
|
|
|
|
If the object for which the control modes are set is not an asynchronous
|
|
|
|
serial connection, some of the modes may be ignored; for example, if an
|
|
|
|
attempt is made to set the baud rate on a network connection to a
|
|
|
|
terminal on another host, the baud rate may or may not be set on the
|
|
|
|
connection between that terminal and the machine it is directly connected
|
|
|
|
to.
|
|
|
|
.Ss Local Modes
|
|
|
|
Values of the
|
|
|
|
.Fa c_lflag
|
|
|
|
field describe the control of
|
|
|
|
various functions, and are composed of the following
|
|
|
|
masks.
|
|
|
|
.Pp
|
|
|
|
.Bl -tag -width NOKERNINFO -offset indent -compact
|
|
|
|
.It Dv ECHOKE
|
|
|
|
/* visual erase for line kill */
|
|
|
|
.It Dv ECHOE
|
|
|
|
/* visually erase chars */
|
|
|
|
.It Dv ECHO
|
|
|
|
/* enable echoing */
|
|
|
|
.It Dv ECHONL
|
|
|
|
/* echo
|
|
|
|
.Dv NL
|
|
|
|
even if
|
|
|
|
.Dv ECHO
|
|
|
|
is off */
|
|
|
|
.It Dv ECHOPRT
|
|
|
|
/* visual erase mode for hardcopy */
|
|
|
|
.It Dv ECHOCTL
|
|
|
|
/* echo control chars as ^(Char) */
|
|
|
|
.It Dv ISIG
|
|
|
|
/* enable signals
|
|
|
|
.Dv INTR ,
|
|
|
|
.Dv QUIT ,
|
|
|
|
.Dv [D]SUSP
|
|
|
|
*/
|
|
|
|
.It Dv ICANON
|
|
|
|
/* canonicalize input lines */
|
|
|
|
.It Dv ALTWERASE
|
|
|
|
/* use alternate
|
|
|
|
.Dv WERASE
|
|
|
|
algorithm */
|
|
|
|
.It Dv IEXTEN
|
|
|
|
/* enable
|
|
|
|
.Dv DISCARD
|
|
|
|
and
|
|
|
|
.Dv LNEXT
|
|
|
|
*/
|
|
|
|
.It Dv EXTPROC
|
|
|
|
/* external processing */
|
|
|
|
.It Dv TOSTOP
|
|
|
|
/* stop background jobs from output */
|
|
|
|
.It Dv FLUSHO
|
|
|
|
/* output being flushed (state) */
|
|
|
|
.It Dv NOKERNINFO
|
|
|
|
/* no kernel output from
|
|
|
|
.Dv VSTATUS
|
|
|
|
*/
|
|
|
|
.It Dv PENDIN
|
|
|
|
/* XXX retype pending input (state) */
|
|
|
|
.It Dv NOFLSH
|
|
|
|
/* don't flush after interrupt */
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHO
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, input characters are echoed back to the terminal.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ECHO
|
|
|
|
is not set, input characters are not echoed.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHOE
|
|
|
|
and
|
|
|
|
.Dv ICANON
|
|
|
|
are set, the
|
|
|
|
.Dv ERASE
|
|
|
|
character causes the terminal
|
|
|
|
to erase the last character in the current line from the display, if
|
2003-06-28 23:53:39 +00:00
|
|
|
possible.
|
|
|
|
If there is no character to erase, an implementation may echo
|
1994-05-30 19:09:18 +00:00
|
|
|
an indication that this was the case or do nothing.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHOK
|
|
|
|
and
|
|
|
|
.Dv ICANON
|
|
|
|
are set, the
|
|
|
|
.Dv KILL
|
|
|
|
character causes
|
|
|
|
the current line to be discarded and the system echoes the
|
|
|
|
.Ql \&\en
|
|
|
|
character after the
|
|
|
|
.Dv KILL
|
|
|
|
character.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHOKE
|
|
|
|
and
|
|
|
|
.Dv ICANON
|
|
|
|
are set, the
|
|
|
|
.Dv KILL
|
|
|
|
character causes
|
|
|
|
the current line to be discarded and the system causes
|
|
|
|
the terminal
|
|
|
|
to erase the line from the display.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHOPRT
|
|
|
|
and
|
|
|
|
.Dv ICANON
|
|
|
|
are set, the system assumes
|
|
|
|
that the display is a printing device and prints a
|
|
|
|
backslash and the erased characters when processing
|
|
|
|
.Dv ERASE
|
|
|
|
characters, followed by a forward slash.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHOCTL
|
|
|
|
is set, the system echoes control characters
|
|
|
|
in a visible fashion using a caret followed by the control character.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ALTWERASE
|
|
|
|
is set, the system uses an alternative algorithm
|
|
|
|
for determining what constitutes a word when processing
|
|
|
|
.Dv WERASE
|
|
|
|
characters (see
|
|
|
|
.Dv WERASE ) .
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ECHONL
|
|
|
|
and
|
|
|
|
.Dv ICANON
|
|
|
|
are set, the
|
|
|
|
.Ql \&\en
|
|
|
|
character echoes even if
|
|
|
|
.Dv ECHO
|
|
|
|
is not set.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ICANON
|
2003-06-28 23:53:39 +00:00
|
|
|
is set, canonical processing is enabled.
|
|
|
|
This enables the
|
1994-05-30 19:09:18 +00:00
|
|
|
erase and kill edit functions, and the assembly of input characters into
|
|
|
|
lines delimited by
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv NL ,
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv EOF ,
|
|
|
|
and
|
2001-02-01 16:38:02 +00:00
|
|
|
.Dv EOL ,
|
1994-05-30 19:09:18 +00:00
|
|
|
as described in
|
|
|
|
.Sx "Canonical Mode Input Processing" .
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ICANON
|
|
|
|
is not set, read requests are satisfied directly from the input
|
2003-06-28 23:53:39 +00:00
|
|
|
queue.
|
|
|
|
A read is not satisfied until at least
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv MIN
|
1994-05-30 19:09:18 +00:00
|
|
|
bytes have been
|
|
|
|
received or the timeout value
|
1997-03-18 07:17:22 +00:00
|
|
|
.Dv TIME
|
2003-06-28 23:53:39 +00:00
|
|
|
expired between bytes.
|
|
|
|
The time value
|
2004-07-03 18:29:24 +00:00
|
|
|
represents tenths of seconds.
|
|
|
|
See
|
1994-05-30 19:09:18 +00:00
|
|
|
.Sx "Noncanonical Mode Input Processing"
|
|
|
|
for more details.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv ISIG
|
|
|
|
is set, each input character is checked against the special
|
|
|
|
control characters
|
|
|
|
.Dv INTR ,
|
|
|
|
.Dv QUIT ,
|
|
|
|
and
|
|
|
|
.Dv SUSP
|
2003-06-28 23:53:39 +00:00
|
|
|
(job control only).
|
|
|
|
If an input
|
1994-05-30 19:09:18 +00:00
|
|
|
character matches one of these control characters, the function
|
2003-06-28 23:53:39 +00:00
|
|
|
associated with that character is performed.
|
|
|
|
If
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv ISIG
|
|
|
|
is not set, no
|
2003-06-28 23:53:39 +00:00
|
|
|
checking is done.
|
|
|
|
Thus these special input functions are possible only
|
1994-05-30 19:09:18 +00:00
|
|
|
if
|
|
|
|
.Dv ISIG
|
|
|
|
is set.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv IEXTEN
|
|
|
|
is set, implementation-defined functions are recognized
|
2003-06-28 23:53:39 +00:00
|
|
|
from the input data.
|
|
|
|
How
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv IEXTEN
|
|
|
|
being set
|
|
|
|
interacts with
|
|
|
|
.Dv ICANON ,
|
|
|
|
.Dv ISIG ,
|
|
|
|
.Dv IXON ,
|
|
|
|
or
|
|
|
|
.Dv IXOFF
|
|
|
|
is implementation defined.
|
|
|
|
If
|
|
|
|
.Dv IEXTEN
|
|
|
|
is not set, then
|
|
|
|
implementation-defined functions are not recognized, and the
|
|
|
|
corresponding input characters are not processed as described for
|
|
|
|
.Dv ICANON ,
|
|
|
|
.Dv ISIG ,
|
|
|
|
.Dv IXON ,
|
|
|
|
and
|
|
|
|
.Dv IXOFF .
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv NOFLSH
|
|
|
|
is set, the normal flush of the input and output queues
|
|
|
|
associated with the
|
|
|
|
.Dv INTR ,
|
|
|
|
.Dv QUIT ,
|
|
|
|
and
|
|
|
|
.Dv SUSP
|
|
|
|
characters
|
|
|
|
are not be done.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv TOSTOP
|
|
|
|
is set, the signal
|
|
|
|
.Dv SIGTTOU
|
|
|
|
is sent to the process group of a process that tries to write to
|
|
|
|
its controlling terminal if it is not in the foreground process group for
|
2003-06-28 23:53:39 +00:00
|
|
|
that terminal.
|
|
|
|
This signal, by default, stops the members of the process group.
|
|
|
|
Otherwise, the output generated by that process is output to the
|
|
|
|
current output stream.
|
|
|
|
Processes that are blocking or ignoring
|
1994-05-30 19:09:18 +00:00
|
|
|
.Dv SIGTTOU
|
|
|
|
signals are excepted and allowed to produce output and the
|
|
|
|
.Dv SIGTTOU
|
|
|
|
signal
|
|
|
|
is not sent.
|
|
|
|
.Pp
|
|
|
|
If
|
|
|
|
.Dv NOKERNINFO
|
|
|
|
is set, the kernel does not produce a status message
|
|
|
|
when processing
|
|
|
|
.Dv STATUS
|
|
|
|
characters (see
|
|
|
|
.Dv STATUS ) .
|
|
|
|
.Ss Special Control Characters
|
|
|
|
The special control characters values are defined by the array
|
|
|
|
.Fa c_cc .
|
|
|
|
This table lists the array index, the corresponding special character,
|
2003-06-28 23:53:39 +00:00
|
|
|
and the system default value.
|
|
|
|
For an accurate list of
|
1994-05-30 19:09:18 +00:00
|
|
|
the system defaults, consult the header file
|
2003-09-08 19:57:22 +00:00
|
|
|
.In ttydefaults.h .
|
1994-05-30 19:09:18 +00:00
|
|
|
.Pp
|
|
|
|
.Bl -column "Index Name" "Special Character" -offset indent -compact
|
|
|
|
.It Em "Index Name Special Character Default Value"
|
|
|
|
.It Dv VEOF Ta EOF Ta \&^D
|
|
|
|
.It Dv VEOL Ta EOL Ta _POSIX_VDISABLE
|
|
|
|
.It Dv VEOL2 Ta EOL2 Ta _POSIX_VDISABLE
|
|
|
|
.It Dv VERASE Ta ERASE Ta \&^? Ql \&\e177
|
2004-07-03 18:29:24 +00:00
|
|
|
.It Dv VWERASE Ta WERASE Ta \&^W
|
1994-05-30 19:09:18 +00:00
|
|
|
.It Dv VKILL Ta KILL Ta \&^U
|
|
|
|
.It Dv VREPRINT Ta REPRINT Ta \&^R
|
|
|
|
.It Dv VINTR Ta INTR Ta \&^C
|
|
|
|
.It Dv VQUIT Ta QUIT Ta \&^\e\e Ql \&\e34
|
|
|
|
.It Dv VSUSP Ta SUSP Ta \&^Z
|
|
|
|
.It Dv VDSUSP Ta DSUSP Ta \&^Y
|
|
|
|
.It Dv VSTART Ta START Ta \&^Q
|
|
|
|
.It Dv VSTOP Ta STOP Ta \&^S
|
|
|
|
.It Dv VLNEXT Ta LNEXT Ta \&^V
|
|
|
|
.It Dv VDISCARD Ta DISCARD Ta \&^O
|
|
|
|
.It Dv VMIN Ta --- Ta \&1
|
|
|
|
.It Dv VTIME Ta --- Ta \&0
|
|
|
|
.It Dv VSTATUS Ta STATUS Ta \&^T
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
If the
|
|
|
|
value of one of the changeable special control characters (see
|
|
|
|
.Sx "Special Characters" )
|
|
|
|
is
|
|
|
|
.Dv {_POSIX_VDISABLE} ,
|
|
|
|
that function is disabled; that is, no input
|
|
|
|
data is recognized as the disabled special character.
|
|
|
|
If
|
|
|
|
.Dv ICANON
|
|
|
|
is
|
|
|
|
not set, the value of
|
|
|
|
.Dv {_POSIX_VDISABLE}
|
|
|
|
has no special meaning for the
|
|
|
|
.Dv VMIN
|
|
|
|
and
|
|
|
|
.Dv VTIME
|
|
|
|
entries of the
|
|
|
|
.Fa c_cc
|
|
|
|
array.
|
|
|
|
.Pp
|
|
|
|
The initial values of the flags and control characters
|
2001-07-14 19:41:16 +00:00
|
|
|
after
|
1996-04-08 04:18:31 +00:00
|
|
|
.Fn open
|
|
|
|
is set according to
|
1994-05-30 19:09:18 +00:00
|
|
|
the values in the header
|
2003-09-08 19:57:22 +00:00
|
|
|
.In sys/ttydefaults.h .
|