TCDRAIN(3P) TCDRAIN(3P)
NAME
tcdrain, tcflow, tcflush, tcsendbreak - line control
functions
SYNOPSIS
#include <termios.h>
int tcdrain(fildes)
int fildes;
int tcflow(fildes,action)
int fildes, action;
int tcflush(fildes,queueselector)
int fildes, queueselector;
int tcsendbreak(fildes,duration)
int fildes, duration;
DESCRIPTION
tcdrain causes the process to wait until all output written
to the object indicated by fildes has been transmitted.
tcflow will suspend transmission or reception of data on the
object indicated by fildes, depending on the value of
action. If action is TCOOFF, output will be suspended. If
action is TCOON, suspended output will be restarted. If
action is TCIOF, input will be suspended. If action is
TCION, suspended input will be restarted.
tcflush will discard data written to the object indicated by
fildes but not transmitted, or data received but not read,
depending on the value of queue_selector. If queue_selector
is TCIFLUSH, data received but not read will be flushed. If
queue_selector is TCOFLUSH, data written but not transmitted
will be flushed. If queue_selector is TCIOFLUSH, both data
received but not read and data written but not transmitted
will be flushed.
tcsendbreak will assert a break condition on the serial line
Page 1 May 1989
TCDRAIN(3P) TCDRAIN(3P)
associated with fildes depending on the value of duration.
If duration is zero, the break condition will be asserted
for 0.25 seconds. If duration is not zero, break will last
'duration' milliseconds.
RETURN VALUE
Upon successful completion, zero is returned. Otherwise, -1
is returned and errno is set to indicate the error.
ERRORS
If any of the following conditions occur, -1 will be
returned and errno set to the corresponding value:
[EBADF] fildes is not a valid file descriptor.
[EINVAL] The device does not support the function or if
the function called was tcflush,
queue_selector is invalid.
[ENOTTY] The file associated with fildes is not a
terminal.
tcdrain will report the following error, in addition to
those listed above:
[EINTR] tcdrain was interrupted by a signal.
SEE ALSO
termios(7).
Page 2 May 1989