NAME
tcsendbreak(), tcdrain(), tcflush(), tcflow() — tty line control functions
SYNOPSIS
#include <termios.h>
int tcsendbreak(int fildes, int duration);
int tcdrain(int fildes);
int tcflush(int fildes, int queue_selector);
int tcflow(int fildes, int action);
DESCRIPTION
If the terminal is using asynchronous serial data transmission,
tcsendbreak()
causes transmission of a continuous stream of zero-valued bits
for a specific duration.
If
duration
is zero, it causes transmission of zero-valued bits for at least 0.25 seconds,
but not more than 0.5 seconds.
If
duration
is not zero, zero-valued bits are not transmitted.
tcdrain()
waits until all output written to
fildes
has been transmitted.
tcflush()
discards data written to
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 is flushed.
If
queue_selector
is
TCOFLUSH,
data written but not transmitted is flushed.
If
queue_selector
is
TCIOFLUSH,
both data received but not read, and data written
but not transmitted is flushed.
tcflow()
suspends transmission of data to
fildes
or reception of data from
fildes,
depending on the value of
action:
If
action
is
TCOOFF,
output is suspended.
If
action
is
TCOON,
suspended output is restarted.
If
action
is
TCIOFF,
a
STOP
character is transmitted
which is intended to cause the terminal
to stop transmitting data to the system.
If
action
is
TCION,
a
START
character is transmitted
which is intended to cause the terminal
to start transmitting data to the system.
RETURN VALUE
Upon successful completion, a value of zero is returned.
Otherwise, a value of -1 is returned and
errno
is set to indicate the error.
ERRORS
These functions fail if one or more of the following is true:
- [EBADF]
fildes
is not a valid file descriptor.
- [EINTR]
A signal was received during
tcdrain().
- [EINVAL]
The
queue_selector
or the
action
argument is not a proper value.
- [ENOTTY]
The file associated with
fildes
is not a terminal.
STANDARDS CONFORMANCE
tcdrain(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
tcflow(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
tcflush(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
tcsendbreak(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
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