NAME
tcsendbreak,
tcdrain, tcflush,
tcflow —
line control functions
LIBRARY
library “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
Thetcdrain 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
tcdrainfunction.
SEE ALSO
STANDARDS
The tcsendbreak,
tcdrain, tcflush and
tcflow functions are expected to be compliant with
the IEEE Std 1003.1-1988 (“POSIX.1”)
specification.