TCSENDBREAK(3) BSD Library Functions Manual TCSENDBREAK(3)
tcsendbreak, tcdrain, tcflush, tcflow -- line control functions
Standard C Library (libc, -lc)
tcflow(int fd, int action);
tcflush(int fd, int action);
tcsendbreak(int fd, int len);
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 ter-
minal referenced by fd depending on the value of action. The value of action must be one of
TCOOFF Suspend output.
TCOON Restart suspended output.
TCIOFF Transmit a STOP character, which is intended to cause the terminal to stop transmit-
ting data to the system. (See the description of IXOFF in the 'Input Modes' section
TCION Transmit a START character, which is intended to cause the terminal to start trans-
mitting data to the system. (See the description of IXOFF in the 'Input Modes' sec-
tion 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 imple-
Upon successful completion, all of these functions return a value of zero.
If any error occurs, a value of -1 is returned and the global variable errno is set to indi-
cate 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.
The tcsendbreak, tcdrain, tcflush and tcflow functions are expected to be compliant with the
IEEE Std 1003.1-1988 (``POSIX.1'') specification.
BSD June 4, 1993 BSD