"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, the tcsendbreak() function shall cause transmission of a continuous stream of zero-valued bits for a specific duration. If duration is zero, it shall cause transmission of zero-valued bits for at least 0.25 seconds, and not more that 0.5 seconds.

The tcdrain() function shall wait until all output written to the object referred to by fildes has been transmitted.

Upon successful completion, the tcflush() function shall have discarded any data written to the object referred to by fildes but not transmitted, or data received but not read, depending on the value of queue_selector:

 (1) If queue_selector is TCIFLUSH, it shall flush data received but
 not read.

 (2) If queue_selector is TCOFLUSH, it shall flush data written but
 not transmitted.

 (3) If queue_selector is TCIOFLUSH, it shall flush both data
 received but not read, and data written but not transmitted.

The tcflow() function shall suspend transmission or reception of data on the object referred to by fildes, depending on the value of action:

 (1) If action is TCOOFF, it shall suspend output.

 (2) If action is TCOON, it shall restart suspended output.

 (3) If action is TCIOFF, the system shall transmit a STOP character,
 which is intended to cause the terminal device to stop
 transmitting data to the system. (See the description of IXOFF
 in "Input Modes".)

 (4) If action is TCION, the system shall transmit a START character,
 which is intended to cause the terminal device to start
 transmitting data to the system. (See the description of IXOFF
 in "Input Modes".)

"Returns"

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"

If any of the following conditions occur, the tcsendbreak() function shall return -1 and set errno to the corresponding value:

 [EBADF] The fildes argument is not a valid file descriptor.

 [ENOTTY] The file associated with fildes is not a terminal.

If any of the following conditions occur, the tcdrain() function shall return -1 and set errno to the corresponding value:

 [EBADF] The fildes argument is not a valid file descriptor.

 [EINTR] A signal interrupted the tcdrain() function.

 [ENOTTY] The file associated with fildes is not a terminal.

If any of the following conditions occur, the tcflush() function shall return -1 and set errno to the corresponding value:

 [EBADF] The fildes argument is not a valid file descriptor.

 [EINVAL] The queue_selector argument is not a proper value.

 [ENOTTY] The file associated with fildes is not a terminal.

If any of the following conditions occur, the tcflow() function shall return -1 and set errno to the corresponding value:

 [EBADF] The fildes argument is not a valid file descriptor.

 [EINVAL] The action argument is not a proper value.

 [ENOTTY] The file associated with fildes is not a terminal.