Manual Pages for UNIX Operating System command usage for man tcsetattr

Standard C Library Functions                        tcsetattr(3C)



NAME
     tcsetattr - set the parameters associated with the terminal

SYNOPSIS
     #include 

     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  implemen-
     tation 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



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Standard C Library Functions                        tcsetattr(3C)



     to  tcgetattr(3C) will return the actual state of the termi-
     nal 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   tcgetattr(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 terminal, 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  descrip-
               tor.


     EINTR     A signal interrupted tcsettattr().


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



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Standard C Library Functions                        tcsetattr(3C)



     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  attri-
     butes:



     ______________________________________________________________
    |       ATTRIBUTE TYPE        |        ATTRIBUTE VALUE        |
    |_____________________________|_______________________________|
    | Interface Stability         | Committed                     |
    |_____________________________|_______________________________|
    | MT-Level                    | MT-Safe, and Async-Signal-Safe|
    |_____________________________|_______________________________|
    | Standard                    | See standards(5).             |
    |_____________________________|_______________________________|


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
























SunOS 5.11          Last change: 14 Aug 2002                    3