tcsetattr(3C)						   Standard C Library Functions 					     tcsetattr(3C)

NAME

       tcsetattr - set the parameters associated with the terminal

SYNOPSIS

       #include <termios.h>

       int tcsetattr(int fildes, int optional_actions, const struct termios *termios_p);

DESCRIPTION

       The  tcsetattr()  function  sets  the  parameters associated with the terminal referred to by the open file descriptor fildes (an open file
       descriptor associated with a terminal) from the termios structure (see termio(7I)) referenced by termios_p as follows:

	 o  If optional_actions is TCSANOW, the change will occur immediately.

	 o  If optional_actions is TCSADRAIN, the change will occur after all output written to fildes is transmitted.	This  function	should	be
	    used when changing parameters that affect output.

	 o  If	optional_actions  is  TCSAFLUSH,  the  change  will  occur after all output written to fildes is transmitted, and all input so far
	    received but not read will be discarded before the change is made.

       If the output baud rate stored in the termios structure pointed to by termios_p is the zero baud rate, B0, the modem control lines will	no
       longer be asserted. Normally, this will disconnect the line.

       If  the input baud rate stored in the termios structure pointed to by termios_p is 0, the input baud rate given to the hardware will be the
       same as the output baud rate stored in the termios structure.

       The tcsetattr() function will return successfully if it was able to perform any of the requested actions, even if  some	of  the  requested
       actions	could  not be performed. It will set all the attributes that implementation supports as requested and leave all the attributes not
       supported by the implementation unchanged. If no part of the request can be honoured, it will return -1 and set errno  to  EINVAL.  If  the
       input  and  output baud rates differ and are a combination that is not supported, neither baud rate is changed.	A subsequent call to tcge-
       tattr(3C) will return the actual state of the terminal device (reflecting both the changes made and not made in	the  previous  tcsetattr()
       call).  The tcsetattr() function will not change the values in the termios structure whether or not it actually accepts them.

       The  effect  of tcsetattr() is undefined if the value of the termios structure pointed to by termios_p was not derived from the result of a
       call to tcgetattr(3C) on fildes; an application should modify only fields and flags defined by this document  between  the  call  to  tcge-
       tattr(3C) and tcsetattr(), leaving all other fields and flags unmodified.

       No  actions defined by this document, other than a call to tcsetattr() or a close of the last file descriptor in the system associated with
       this terminal device, will cause any of the terminal attributes defined by this document to change.

       Attempts to use tcsetattr() from a process which is a member of a background process group on a fildes associated with its controlling ter-
       minal,  will  cause  the  process  group  to  be sent a SIGTTOU signal. If the calling process is blocking or ignoring SIGTTOU signals, the
       process is allowed to perform the operation, and no signal is sent.

USAGE

       If trying to change baud rates, applications should call tcsetattr() then call tcgetattr(3C) in order to determine  what  baud  rates  were
       actually selected.

RETURN VALUES

       Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The tcsetattr() function will fail if:

       EBADF	       The fildes argument is not a valid file descriptor.

       EINTR	       A signal interrupted tcsettattr().

       EINVAL	       The  optional_actions  argument	is not a supported value, or an attempt was made to change an attribute represented in the
		       termios structure to an unsupported value.

       ENOTTY	       The file associated with fildes is not a terminal.

       The tcsetattr() function may fail if:

       EIO	       The process group of the writing process is orphaned, and the writing process is not ignoring or blocking SIGTTOU.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-------------------------------+
       |      ATTRIBUTE TYPE	     |	     ATTRIBUTE VALUE	     |
       +-----------------------------+-------------------------------+
       |Interface Stability	     |Standard			     |
       +-----------------------------+-------------------------------+
       |MT-Level		     |MT-Safe, and Async-Signal-Safe |
       +-----------------------------+-------------------------------+

SEE ALSO

       cfgetispeed(3C), tcgetattr(3C), attributes(5), standards(5), termio(7I)

SunOS 5.10							    14 Aug 2002 						     tcsetattr(3C)