TCDRAIN(P) POSIX Programmer's Manual TCDRAIN(P)
tcdrain - wait for transmission of output
int tcdrain(int fildes);
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
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 sig-
nals, the process shall be allowed to perform the operation, and no signal is sent.
Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and errno
set to indicate the error.
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.
tcflush() , the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 11, General Ter-
minal Interface, <termios.h>, <unistd.h>
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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 TCDRAIN(P)