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TCSETATTR(3)	       FreeBSD Library Functions Manual		  TCSETATTR(3)

NAME
     cfgetispeed, cfsetispeed, cfgetospeed, cfsetospeed, cfsetspeed,
     cfmakeraw,	cfmakesane, tcgetattr, tcsetattr -- manipulating the termios
     structure

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <termios.h>

     speed_t
     cfgetispeed(const struct termios *t);

     int
     cfsetispeed(struct	termios	*t, speed_t speed);

     speed_t
     cfgetospeed(const struct termios *t);

     int
     cfsetospeed(struct	termios	*t, speed_t speed);

     int
     cfsetspeed(struct termios *t, speed_t speed);

     void
     cfmakeraw(struct termios *t);

     void
     cfmakesane(struct termios *t);

     int
     tcgetattr(int fd, struct termios *t);

     int
     tcsetattr(int fd, int action, const struct	termios	*t);

DESCRIPTION
     The cfmakeraw(), cfmakesane(), tcgetattr()	and tcsetattr()	functions are
     provided for getting and setting the termios structure.

     The cfgetispeed(),	cfsetispeed(), cfgetospeed(), cfsetospeed() and
     cfsetspeed() functions are	provided for getting and setting the baud rate
     values in the termios structure.  The effects of the functions on the
     terminal as described below do not	become effective, nor are all errors
     detected, until the tcsetattr() function is called.  Certain values for
     baud rates	set in the termios structure and passed	to tcsetattr() have
     special meanings.	These are discussed in the portion of the manual page
     that describes the	tcsetattr() function.

GETTING	AND SETTING THE	BAUD RATE
     The input and output baud rates are found in the termios structure.  The
     unsigned integer speed_t is typedef'd in the include file <termios.h>.
     The value of the integer corresponds directly to the baud rate being rep-
     resented, however,	the following symbolic values are defined.

     #define B0	     0
     #define B50     50
     #define B75     75
     #define B110    110
     #define B134    134
     #define B150    150
     #define B200    200
     #define B300    300
     #define B600    600
     #define B1200   1200
     #define B1800   1800
     #define B2400   2400
     #define B4800   4800
     #define B9600   9600
     #define B19200  19200
     #define B38400  38400
     #ifndef _POSIX_SOURCE
     #define EXTA    19200
     #define EXTB    38400
     #endif  /*_POSIX_SOURCE */

     The cfgetispeed() function	returns	the input baud rate in the termios
     structure referenced by tp.

     The cfsetispeed() function	sets the input baud rate in the	termios	struc-
     ture referenced by	tp to speed.

     The cfgetospeed() function	returns	the output baud	rate in	the termios
     structure referenced by tp.

     The cfsetospeed() function	sets the output	baud rate in the termios
     structure referenced by tp	to speed.

     The cfsetspeed() function sets both the input and output baud rate	in the
     termios structure referenced by tp	to speed.

     Upon successful completion, the functions cfsetispeed(), cfsetospeed(),
     and cfsetspeed() return a value of	0.  Otherwise, a value of -1 is
     returned and the global variable errno is set to indicate the error.

GETTING	AND SETTING THE	TERMIOS	STATE
     This section describes the	functions that are used	to control the general
     terminal interface.  Unless otherwise noted for a specific	command, these
     functions are restricted from use by background processes.	 Attempts to
     perform these operations shall cause the process group to be sent a SIGT-
     TOU signal.  If the calling process is blocking or	ignoring SIGTTOU sig-
     nals, the process is allowed to perform the operation and the SIGTTOU
     signal is not sent.

     In	all the	functions, although fd is an open file descriptor, the func-
     tions affect the underlying terminal file,	not just the open file
     description associated with the particular	file descriptor.

     The cfmakeraw() function sets the flags stored in the termios structure
     to	a state	disabling all input and	output processing, giving a ``raw I/O
     path'', while the cfmakesane() function sets them to a state similar to
     those of a	newly created terminal device.	It should be noted that	there
     is	no function to reverse this effect.  This is because there are a vari-
     ety of processing options that could be re-enabled	and the	correct	method
     is	for an application to snapshot the current terminal state using	the
     function tcgetattr(), setting raw or sane mode with cfmakeraw() or
     cfmakesane() and the subsequent tcsetattr(), and then using another
     tcsetattr() with the saved	state to revert	to the previous	terminal
     state.

     The tcgetattr() function copies the parameters associated with the	termi-
     nal referenced by fd in the termios structure referenced by tp.  This
     function is allowed from a	background process, however, the terminal
     attributes	may be subsequently changed by a foreground process.

     The tcsetattr() function sets the parameters associated with the terminal
     from the termios structure	referenced by tp.  The action argument is cre-
     ated by or'ing the	following values, as specified in the include file
     <termios.h>.

     TCSANOW	The change occurs immediately.

     TCSADRAIN	The change occurs after	all output written to fd has been
		transmitted to the terminal.  This value of action should be
		used when changing parameters that affect output.

     TCSAFLUSH	The change occurs after	all output written to fd has been
		transmitted to the terminal.  Additionally, any	input that has
		been received but not read is discarded.

     TCSASOFT	If this	value is or'ed into the	action value, the values of
		the c_cflag, c_ispeed, and c_ospeed fields are ignored.

     The 0 baud	rate is	used to	terminate the connection.  If 0	is specified
     as	the output speed to the	function tcsetattr(), modem control will no
     longer be asserted	on the terminal, disconnecting the terminal.

     If	zero is	specified as the input speed to	the function tcsetattr(), the
     input baud	rate will be set to the	same value as that specified by	the
     output baud rate.

     If	tcsetattr() is unable to make any of the requested changes, it returns
     -1	and sets errno.	 Otherwise, it makes all of the	requested changes it
     can.  If the specified input and output baud rates	differ and are a com-
     bination that is not supported, neither baud rate is changed.

     Upon successful completion, the functions tcgetattr() and tcsetattr()
     return a value of 0.  Otherwise, they return -1 and the global variable
     errno is set to indicate the error, as follows:

     [EBADF]		The fd argument	to tcgetattr() or tcsetattr() was not
			a valid	file descriptor.

     [EINTR]		The tcsetattr()	function was interrupted by a signal.

     [EINVAL]		The action argument to the tcsetattr() function	was
			not valid, or an attempt was made to change an
			attribute represented in the termios structure to an
			unsupported value.

     [ENOTTY]		The file associated with the fd	argument to
			tcgetattr() or tcsetattr() is not a terminal.

SEE ALSO
     tcsendbreak(3), termios(4)

STANDARDS
     The cfgetispeed(),	cfsetispeed(), cfgetospeed(), cfsetospeed(),
     tcgetattr() and tcsetattr() functions are expected	to be compliant	with
     the IEEE Std 1003.1-1988 (``POSIX.1'') specification.  The	cfmakeraw(),
     cfmakesane() and cfsetspeed() functions, as well as the TCSASOFT option
     to	the tcsetattr()	function are extensions	to the IEEE Std	1003.1-1988
     (``POSIX.1'') specification.

FreeBSD	10.1			January	2, 1994			  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | GETTING AND SETTING THE BAUD RATE | GETTING AND SETTING THE TERMIOS STATE | SEE ALSO | STANDARDS

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