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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 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 tcdrain() function shall fail if:
EBADF The fildes argument is not a valid file descriptor.
EINTR A signal interrupted tcdrain().
ENOTTY The file associated with fildes is not a terminal.
The tcdrain() 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
tcflush() , 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 .