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.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
XBD V1_chap11(7), <termios.h>
CHANGE HISTORY
First released in Issue 3. Included for alignment with the POSIX.1-1988 standard.
Issue 6
The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:
- In the DESCRIPTION, the final paragraph is no longer conditional on _POSIX_JOB_CONTROL. This is a FIPS requirement.
- The [EIO] error is added.
Issue 7
POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0639 [79], XSH/TC1-2008/0640 [79], and XSH/TC1-2008/0641 [79] are applied.