NAME

       tcflush - flush non-transmitted output data, non-read input data, or both

SYNOPSIS

       #include <termios.h>

       int tcflush(int fildes, int queue_selector);

DESCRIPTION

       Upon successful completion, tcflush() shall discard data written to the object referred to
       by fildes (an open file descriptor associated with a terminal)  but  not  transmitted,  or
       data received but not read, depending on the value of queue_selector:

        * If queue_selector is TCIFLUSH, it shall flush data received but not read.

        * If queue_selector is TCOFLUSH, it shall flush data written but not transmitted.

        * If queue_selector is TCIOFLUSH, it shall flush both data received but not read and data
          written but not transmitted.

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

RETURN VALUE

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

ERRORS

       The tcflush() function shall fail if:

       EBADF  The fildes argument is not a valid file descriptor.

       EINVAL The queue_selector argument is not a supported value.

       ENOTTY The file associated with fildes is not a terminal.

       The tcflush() function may fail if:

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

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       tcdrain()  ,  the  Base  Definitions  volume  of IEEE Std 1003.1-2001, Chapter 11, General
       Terminal Interface, <termios.h>, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2003  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .