Guaranteed Launch

Question

In Cost of weak pointers and finalizers at the GHC , writes Edward Yang (emphasis added):

A weak pointer can also be associated with a finalizer that starts when an object collects garbage. Haskell finalizers are not guaranteed.

I can’t find any documentation supporting this claim. The docs System.Mem.Weakare not explicitly about this. What I need to know is some entity that has the identity ( MutVar#, MutableArray#, Array#etc.) If I am attached to it finalizer if he will be safely called when the value gets GCed?

The reason is because I plan to do something like this:

data OffHeapTree = OffHeapTree
  { ref :: IORef ()
  , nodeCount :: Int
  , nodeArray :: Ptr Node
  }

data Node = Node
  { childrenArray :: Ptr Node
  , childrenCount :: Int
  , value :: Int
  }

, ( , ), OffHeapTree . . , mkWeakIORef ?

Answer 1

" Haskell " , GC (, ). GC, .

: : . RTS GC. , GC, , . .

. , . RTS , . , .