F#: is there a way to mark a ref cell contents as volatile?

Question

I've come across a situation where a ref cell containing a boolean allows me to quite conveniently solve a problem of telling a spin-waiting loop to stop spin-waiting. I need to mark this flag as volatile (i.e. [<VolatileField>]) but such a field needs to be mutable according to the compiler, which is exactly what I don't want the reference to be -- I want its contents to be mutable, not the reference cell field itself.

Is there a standard way of telling a ref cell to mark its contents as volatile or do I need to roll my own ref cell (i.e. copy-paste the standard ref cell definition with [<VolatileField>] stuck just above mutable contents)? Well, correcting that for the fact that you cannot mark record fields as volatile...

Answer 1

Volatile. or Interlocked. methods just work fine with ref cells:

open System.Threading

let refCell = ref 0

Volatile.Write(refCell, 42)
let fortyTwo = Volatile.Read(refCell)

You do not even need & or ! before ref cells variable names, they are already references. Volatile and Interlocked methods are easier to reason about than [<VolatileField>] as described here.