How to set and clear the break bit

[dignifiedquire]

I need to set and clear the break bit, which should be possibl on linux at least using TIOCSBRK and TIOCCBRK

Asfaict this is not exposed, but could be through the internal set_pin functionality

References

• https://stackoverflow.com/questions/72012002/is-it-possible-to-programatically-hold-the-serial-port-tx-line-high-or-low-in-c
• https://linux.die.net/man/4/tty_ioctl

[de-vri-es]

Hey! Thanks for reporting the issue.

Currently you can not force a break condition using serial2. I think this definitely needs to be fixed.

However, there is no break "bit". A break condition is when a transmitter holds it's line in a logical 0 state for more than a whole byte.

We have a few options to model this. One is to have a function to hold the line in break condition for a given amount of time. Advantage is that it's hard to mis-use. You won't accidentally hold the line in break condition, since the function itself will clear it.

But such a function would also block the current thread, which is a bit of a waste. So toggling the break condition on/off might be a better API.

However, keep in mind that the API needs to be possible on Windows too.

I see you started on a PR already. Would you like to continue with that? :)

/edit: Windows has SetCommBreak and ClearCommBreak