int tcsendbreak(int fildes, int duration);
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.
Upon successful completion,
0 shall be returned. Otherwise,
-1 shall be returned and
errno set to indicate the error.
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
ENOTTY- The file associated with fildes is not a terminal.