TCFLUSH(3P)                                         POSIX Programmer's Manual                                        TCFLUSH(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

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, Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   TCFLUSH(3P)