[solved] save axis position as offset when pushing a button

I'd like to set a Hal-value (float) to the current absolute axis position when I press a button.

Or to put it differently:

"sets myvalue joint.0.pos-fb" IF 'myhalpin = TRUE"

Can I do this in HAL or do I have to go through classic-ladder?

Thanks

I'm not sure I understand your question.
Maybe I worded my question wrong.
joint.0.pos-fb is an output pin.

So in hal I could do:
sets myvalue 100

but I would like 'myvalue' to store the current value of joint.0.pos-fb when I push a button.

Ooops,
no I would actually like to store the present absolute value of my x-axis in a variable when I press a button to use it as an offset. I don't know what I was looking at.
But the question is really how to store a float value in Hal when another pin goes true.

I think he wants to store the value of FB pin at any given time when he presses a button on a panel, right ?
It would be much easier if you told us what the end result should be, this way we are chasing our tails.

Well I thought it was a simple thing that would be used all the time. There is not much more to elaborate on but let me try:
I use 5-axis kinematics and need to set the rotation point while running LinuxCNC. In xyzbc-trt kinematics there are two offset-pins in HAL to define the point of rotation for the B-axis. These are set in the INI file but I have a different setup and need to be able set those values during runtime.
So the X and Z axis are jogged to the required position and then the values need to be set.
So the question is: How do I set a HAL float value when I push a button. Either a pysical input or a gladevcp panel button.

That is more understandable, thank you.
It should be possible, seeing as it uses offsets, but i have no idea how.