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 .