The fildes argument is an open file descriptor associated with a terminal.
If the terminal is using asynchronous serial data transmission, tcsendbreak() will cause transmission of a continuous stream of zero-valued bits for a specific duration. If duration is 0, it will 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 behaves in a way
similar to tcdrain(3C).
If the terminal is not using asynchronous serial data transmission, it 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 will
cause the process group to be sent a SIGTTOU signal. If the calling process is blocking or ignoring SIGTTOU signals, the
process is allowed to perform the operation, and no signal is sent.
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