[PD-dev] Scheduling to activate control objects

Hi,

I am working on a control rate object which outputs a value, only when a variable local to each instance is modified by another thread.

Having not known how to achieve this, the object works fine, but only with a [metro] connected to it, polling for a variable change on each bang.

I've looked into [metro] and [netreceive] which also output values without an external factor (inlet wise), but I kind of got lost in the code.

Is there a simple way of achieving such an effect (i.e. by registering a callback), or does this require a reasonable understanding of the time scheduling mechanism inside Pd?

Any advise is appreciated.

Thank you.