1TCDRAIN(3P)                POSIX Programmer's Manual               TCDRAIN(3P)
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PROLOG

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

12       tcdrain — wait for transmission of output
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SYNOPSIS

15       #include <termios.h>
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17       int tcdrain(int fildes);
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DESCRIPTION

20       The tcdrain() function shall block until  all  output  written  to  the
21       object  referred to by fildes is transmitted. The fildes argument is an
22       open file descriptor associated with a terminal.
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24       Any attempts to use tcdrain() from a process which is  a  member  of  a
25       background  process  group  on a fildes associated with its controlling
26       terminal, shall cause the process group to be sent  a  SIGTTOU  signal.
27       If  the  calling  thread  is blocking SIGTTOU signals or the process is
28       ignoring SIGTTOU signals, the process shall be allowed to  perform  the
29       operation, and no signal is sent.
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RETURN VALUE

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

36       The tcdrain() function shall fail if:
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38       EBADF  The fildes argument is not a valid file descriptor.
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40       EINTR  A signal interrupted tcdrain().
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42       EIO    The process group of the writing process is orphaned, the  call‐
43              ing  thread  is  not  blocking  SIGTTOU,  and the process is not
44              ignoring SIGTTOU.
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46       ENOTTY The file associated with fildes is not a terminal.
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48       The following sections are informative.
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EXAMPLES

51       None.
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APPLICATION USAGE

54       None.
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RATIONALE

57       None.
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FUTURE DIRECTIONS

60       None.
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SEE ALSO

63       tcflush()
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65       The Base Definitions volume of POSIX.1‐2017, Chapter 11, General Termi‐
66       nal Interface, <termios.h>
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69       Portions  of  this text are reprinted and reproduced in electronic form
70       from IEEE Std 1003.1-2017, Standard for Information Technology --  Por‐
71       table  Operating System Interface (POSIX), The Open Group Base Specifi‐
72       cations Issue 7, 2018 Edition, Copyright (C) 2018 by the  Institute  of
73       Electrical  and  Electronics Engineers, Inc and The Open Group.  In the
74       event of any discrepancy between this version and the original IEEE and
75       The  Open Group Standard, the original IEEE and The Open Group Standard
76       is the referee document. The original Standard can be  obtained  online
77       at http://www.opengroup.org/unix/online.html .
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79       Any  typographical  or  formatting  errors that appear in this page are
80       most likely to have been introduced during the conversion of the source
81       files  to  man page format. To report such errors, see https://www.ker‐
82       nel.org/doc/man-pages/reporting_bugs.html .
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86IEEE/The Open Group                  2017                          TCDRAIN(3P)
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