TCDRAIN(3)                 POSIX Programmer's Manual                TCDRAIN(3)



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

NAME
       tcdrain -- wait for transmission of output

SYNOPSIS
       #include <termios.h>

       int tcdrain(int fildes);

DESCRIPTION
       The tcdrain() function shall block until all output written to the
       object referred to by fildes is transmitted. The fildes argument is an
       open file descriptor associated with a terminal.

       Any attempts to use tcdrain() 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 thread is blocking SIGTTOU signals or the process is
       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 tcdrain() function shall fail if:

       EBADF  The fildes argument is not a valid file descriptor.

       EINTR  A signal interrupted tcdrain().

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

       ENOTTY The file associated with fildes is not a terminal.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       tcflush()

       The Base Definitions volume of POSIX.1-2017, Chapter 11, General
       Terminal Interface, <termios.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                           TCDRAIN(3)
