Recording min/max values from HAL

In order to see how things are working with a newly-tuned system, I'd like to keep track of the min and max error seen from various parameters (eg. following error). Think of it like high (and low) water marks. They would best be persistent, but I could live with them only being active within a session. I should also be able to reset when needed.

At some point in the future when I'm actually making chips with this, I can see this being a useful debugging tool when a part just isn't coming out like it should. At least it could rule out one potential source of error not otherwise easily seen. It will also give me an idea where I can safely set the limits for following error without them tripping at the most inopportune time.

Is there something like this that already exists? If not, could I get some hints on potential implementation?

Pretty sure I got it. I'm not all that surprised that it does, indeed, exist already as the "minmax" HAL component.

linuxcnc.org/docs/html/hal/components.html#_other

Although not yet tested, this thread gives enough to get me going with it.