tcsendbreaktcdraintcflushtcflow
- line control functions
LIBRARY
Lb libc
SYNOPSIS
#include <termios.h> 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
Fa 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
Fa fd
depending on the value of
Fa action .
The value of
Fa action
must be one of the following:
Fa TCOOFF
Suspend output.
Fa TCOON
Restart suspended output.
Fa 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)).
Fa 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
Fa 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
Fa action .
The value of
Fa action
must be one of the following:
Fa TCIFLUSH
Flush data received but not read.
Fa TCOFLUSH
Flush data written but not transmitted.
Fa 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
Fa fd .
The
Fa len
argument 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:
Bq Er EBADF
The
Fa fd
argument is not a valid file descriptor.
