tcsendbreak()

NAME

tcsendbreak(), tcdrain(), tcflow(), tcflush() - line control functions

SYNOPSIS

#include <termios.h>


int tcdrain (int fd)
int tcflow (int fd, int action)
int tcflush (int fd, int queue_selector)
int tcsendbreak (int fd, int len)

DESCRIPTION

These functions control the terminal line, but do not directly affect the terminal attributes (for those, see tcsetattr(2)).

The tcdrain(2) function waits until all output written to the terminal referenced by fd has been transmitted to the terminal.

The tcflow(2) 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.
TCION: Transmit a START character, which is intended to cause the terminal to start transmitting data to the system.

The tcflush(2) 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 queue_selector. The value of queue_selector 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(2) function transmits a continuous stream of zero-valued bits for four-tenths of a second to the terminal referenced by fd.

RETURN VALUES

Upon successful completion, all of these functions return a value of zero. If an error occurs, all of these functions return a value of -1 and set errno

ERRORS

These functions can fail for the following reasons:

[EBADF]: The fd argument is not a valid file descriptor.
[EINVAL]: The action or queue_selector argument is not a proper value.
[ENOTTY]: The file associated with fd is not a terminal.
[EINTR]: A signal interrupted the tcdrain(2) function.