#include <termios.h>

int tcsendbreak(int fildes, int duration);


Partially implemented


IEEE Std 1003.1-2017


tcsendbreak() - send a break for a specific duration

If the terminal is using asynchronous serial data transmission, tcsendbreak() shall cause transmission of a continuous stream of zero-valued bits for a specific duration. If duration is 0, it shall cause transmission of zero-valued bits for at least 0.25 seconds, and not more than 0.5 seconds. If duration is not 0, it shall send zero-valued bits for an implementation-defined period of time.

The fildes argument is an open file descriptor associated with a terminal.

If the terminal is not using asynchronous serial data transmission, it is implementation-defined whether tcsendbreak() sends data to generate a break condition or returns without taking any action.

Attempts to use tcsendbreak() from a process which is a member of a background process group on a fildes associated with its controlling terminal shall cause the process group to be sent a SIGTTOU signal. If the calling thread is blocking SIGTTOU signals or the process is ignoring SIGTTOU signals, the process shall be allowed to perform the operation, and no signal is sent.

Return value#

Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and errno set to indicate the error.


The tcsendbreak() function shall fail if:

  • EBADF - The fildes argument is not a valid file descriptor.

  • EIO - The process group of the writing process is orphaned, the calling thread is not blocking SIGTTOU, and the process is not ignoring SIGTTOU.

  • ENOTTY - The file associated with fildes is not a terminal.



Known bugs#


See Also#

  1. Standard library functions

  2. Table of Contents