NAME
tcsendbreak,
tcdrain,
tcflush,
tcflow
- line control functions
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
int
tcdrain(
int fd
)
int
tcflow(
int fd
, int action
)
int
tcflush(
int fd
, int action
)
int
tcsendbreak(
int fd
, int len
)
DESCRIPTION
The
tcdrain
function waits until all output written to the terminal referenced by
fd
has been transmitted to the terminal.
The
tcflow
function suspends transmission of data to or the reception of data from
the terminal referenced by
fd
depending on the value of
action
.
The value of
action
must be one of the following:
TCOOFF
-
Suspend output.
TCOON
-
Restart suspended output.
TCIOFF
-
Transmit a STOP character, which is intended to cause the terminal to stop
transmitting data to the system.
(See the description of IXOFF in the
`Input Modes'
section of
termios(4)).
TCION
-
Transmit a START character, which is intended to cause the terminal to start
transmitting data to the system.
(See the description of IXOFF in the
`Input Modes'
section of
termios(4)).
The
tcflush
function discards any data written to the terminal referenced by
fd
which has not been transmitted to the terminal, or any data received
from the terminal but not yet read, depending on the value of
action
.
The value of
action
must be one of the following:
TCIFLUSH
-
Flush data received but not read.
TCOFLUSH
-
Flush data written but not transmitted.
TCIOFLUSH
-
Flush both data received but not read and data written but not transmitted.
The
tcsendbreak
function transmits a continuous stream of zero-valued bits for four-tenths
of a second to the terminal referenced by
fd
.
The
len
parameter is ignored in this implementation.
RETURN VALUES
Upon successful completion, all of these functions return a value of zero.
ERRORS
If any error occurs, a value of -1 is returned and the global variable
errno
is set to indicate the error, as follows:
- [
EBADF
] -
The
fd
argument is not a valid file descriptor.
- [
EINVAL
] -
The
action
argument is not a proper value.
- [
ENOTTY
] -
The file associated with
fd
is not a terminal.
- [
EINTR
] -
A signal interrupted the
tcdrain
function.
SEE ALSO
tcsetattr(3),
termios(4)
STANDARDS
The
tcsendbreak,
tcdrain,
tcflush
and
tcflow
functions are expected to be compliant with the
IEEE Std 1003.1-1988 (``POSIX.1'')
specification.