736fc28680
I've noticed various terminal emulators that need to obtain a sane default termios structure use very complex `hacks'. Even though POSIX doesn't provide any functionality for this, extend our termios API with cfmakesane(3), which is similar to the commonly supported cfmakeraw(3), except that it fills the termios structure with sane defaults. Change all code in our base system to use this function, instead of depending on <sys/ttydefaults.h> to provide TTYDEF_*.
341 lines
8.9 KiB
Groff
341 lines
8.9 KiB
Groff
.\" Copyright (c) 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)tcsetattr.3 8.3 (Berkeley) 1/2/94
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.\" $FreeBSD$
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.\"
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.Dd January 2, 1994
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.Dt TCSETATTR 3
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.Os
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.Sh NAME
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.Nm cfgetispeed ,
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.Nm cfsetispeed ,
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.Nm cfgetospeed ,
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.Nm cfsetospeed ,
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.Nm cfsetspeed ,
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.Nm cfmakeraw ,
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.Nm cfmakesane ,
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.Nm tcgetattr ,
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.Nm tcsetattr
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.Nd manipulating the termios structure
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In termios.h
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.Ft speed_t
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.Fn cfgetispeed "const struct termios *t"
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.Ft int
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.Fn cfsetispeed "struct termios *t" "speed_t speed"
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.Ft speed_t
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.Fn cfgetospeed "const struct termios *t"
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.Ft int
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.Fn cfsetospeed "struct termios *t" "speed_t speed"
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.Ft int
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.Fn cfsetspeed "struct termios *t" "speed_t speed"
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.Ft void
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.Fn cfmakeraw "struct termios *t"
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.Ft void
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.Fn cfmakesane "struct termios *t"
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.Ft int
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.Fn tcgetattr "int fd" "struct termios *t"
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.Ft int
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.Fn tcsetattr "int fd" "int action" "const struct termios *t"
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.Sh DESCRIPTION
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The
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.Fn cfmakeraw ,
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.Fn cfmakesane ,
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.Fn tcgetattr
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and
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.Fn tcsetattr
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functions are provided for getting and setting the termios structure.
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.Pp
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The
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.Fn cfgetispeed ,
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.Fn cfsetispeed ,
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.Fn cfgetospeed ,
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.Fn cfsetospeed
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and
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.Fn cfsetspeed
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functions are provided for getting and setting the baud rate values in
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the termios structure.
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The effects of the functions on the terminal as described below
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do not become effective, nor are all errors detected, until the
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.Fn tcsetattr
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function is called.
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Certain values for baud rates set in the termios structure and passed to
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.Fn tcsetattr
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have special meanings.
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These are discussed in the portion of the manual page that describes the
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.Fn tcsetattr
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function.
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.Sh GETTING AND SETTING THE BAUD RATE
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The input and output baud rates are found in the termios structure.
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The unsigned integer
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.Li speed_t
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is typedef'd in the include file
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.In termios.h .
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The value of the integer corresponds directly to the baud rate being
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represented, however, the following symbolic values are defined.
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.Bd -literal
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#define B0 0
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#define B50 50
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#define B75 75
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#define B110 110
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#define B134 134
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#define B150 150
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#define B200 200
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#define B300 300
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#define B600 600
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#define B1200 1200
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#define B1800 1800
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#define B2400 2400
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#define B4800 4800
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#define B9600 9600
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#define B19200 19200
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#define B38400 38400
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#ifndef _POSIX_SOURCE
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#define EXTA 19200
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#define EXTB 38400
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#endif /*_POSIX_SOURCE */
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.Ed
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.Pp
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The
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.Fn cfgetispeed
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function returns the input baud rate in the termios structure referenced by
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.Fa tp .
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.Pp
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The
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.Fn cfsetispeed
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function sets the input baud rate in the termios structure referenced by
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.Fa tp
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to
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.Fa speed .
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.Pp
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The
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.Fn cfgetospeed
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function returns the output baud rate in the termios structure referenced by
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.Fa tp .
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.Pp
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The
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.Fn cfsetospeed
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function sets the output baud rate in the termios structure referenced by
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.Fa tp
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to
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.Fa speed .
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.Pp
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The
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.Fn cfsetspeed
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function sets both the input and output baud rate in the termios structure
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referenced by
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.Fa tp
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to
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.Fa speed .
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.Pp
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Upon successful completion, the functions
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.Fn cfsetispeed ,
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.Fn cfsetospeed ,
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and
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.Fn cfsetspeed
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return a value of 0.
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Otherwise, a value of -1 is returned and the global variable
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.Va errno
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is set to indicate the error.
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.Sh GETTING AND SETTING THE TERMIOS STATE
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This section describes the functions that are used to control the general
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terminal interface.
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Unless otherwise noted for a specific command, these functions are restricted
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from use by background processes.
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Attempts to perform these operations shall cause the process group to be sent
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a SIGTTOU signal.
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If the calling process is blocking or ignoring SIGTTOU signals, the process
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is allowed to perform the operation and the SIGTTOU signal is not sent.
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.Pp
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In all the functions, although
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.Fa fd
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is an open file descriptor, the functions affect the underlying terminal
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file, not just the open file description associated with the particular
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file descriptor.
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.Pp
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The
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.Fn cfmakeraw
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function sets the flags stored in the termios structure to a state disabling
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all input and output processing, giving a
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.Dq raw I/O path ,
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while the
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.Fn cfmakesane
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function sets them to a state similar to those of a newly created
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terminal device.
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It should be noted that there is no function to reverse this effect.
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This is because there are a variety of processing options that could be
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re-enabled and the correct method is for an application to snapshot the
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current terminal state using the function
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.Fn tcgetattr ,
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setting raw or sane mode with
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.Fn cfmakeraw
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or
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.Fn cfmakesane
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and the subsequent
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.Fn tcsetattr ,
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and then using another
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.Fn tcsetattr
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with the saved state to revert to the previous terminal state.
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.Pp
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The
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.Fn tcgetattr
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function copies the parameters associated with the terminal referenced
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by
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.Fa fd
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in the termios structure referenced by
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.Fa tp .
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This function is allowed from a background process, however, the terminal
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attributes may be subsequently changed by a foreground process.
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.Pp
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The
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.Fn tcsetattr
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function sets the parameters associated with the terminal from the
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termios structure referenced by
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.Fa tp .
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The
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.Fa action
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argument is created by
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.Em or Ns 'ing
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the following values, as specified in the include file
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.In termios.h .
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.Bl -tag -width "TCSADRAIN"
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.It Fa TCSANOW
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The change occurs immediately.
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.It Fa TCSADRAIN
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The change occurs after all output written to
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.Fa fd
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has been transmitted to the terminal.
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This value of
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.Fa action
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should be used when changing parameters that affect output.
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.It Fa TCSAFLUSH
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The change occurs after all output written to
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.Fa fd
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has been transmitted to the terminal.
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Additionally, any input that has been received but not read is discarded.
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.It Fa TCSASOFT
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If this value is
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.Em or Ns 'ed
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into the
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.Fa action
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value, the values of the
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.Va c_cflag ,
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.Va c_ispeed ,
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and
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.Va c_ospeed
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fields are ignored.
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.El
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.Pp
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The 0 baud rate is used to terminate the connection.
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If 0 is specified as the output speed to the function
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.Fn tcsetattr ,
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modem control will no longer be asserted on the terminal, disconnecting
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the terminal.
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.Pp
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If zero is specified as the input speed to the function
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.Fn tcsetattr ,
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the input baud rate will be set to the same value as that specified by
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the output baud rate.
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.Pp
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If
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.Fn tcsetattr
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is unable to make any of the requested changes, it returns -1 and
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sets errno.
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Otherwise, it makes all of the requested changes it can.
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If the specified input and output baud rates differ and are a combination
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that is not supported, neither baud rate is changed.
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.Pp
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Upon successful completion, the functions
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.Fn tcgetattr
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and
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.Fn tcsetattr
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return a value of 0.
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Otherwise, they
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return -1 and the global variable
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.Va errno
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is set to indicate the error, as follows:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa fd
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argument to
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.Fn tcgetattr
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or
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.Fn tcsetattr
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was not a valid file descriptor.
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.It Bq Er EINTR
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The
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.Fn tcsetattr
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function was interrupted by a signal.
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.It Bq Er EINVAL
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The
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.Fa action
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argument to the
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.Fn tcsetattr
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function was not valid, or an attempt was made to change an attribute
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represented in the termios structure to an unsupported value.
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.It Bq Er ENOTTY
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The file associated with the
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.Fa fd
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argument to
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.Fn tcgetattr
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or
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.Fn tcsetattr
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is not a terminal.
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.El
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.Sh SEE ALSO
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.Xr tcsendbreak 3 ,
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.Xr termios 4
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.Sh STANDARDS
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The
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.Fn cfgetispeed ,
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.Fn cfsetispeed ,
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.Fn cfgetospeed ,
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.Fn cfsetospeed ,
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.Fn tcgetattr
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and
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.Fn tcsetattr
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functions are expected to be compliant with the
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.St -p1003.1-88
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specification.
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The
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.Fn cfmakeraw ,
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.Fn cfmakesane
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and
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.Fn cfsetspeed
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functions,
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as well as the
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.Li TCSASOFT
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option to the
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.Fn tcsetattr
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function are extensions to the
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.St -p1003.1-88
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specification.
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