Add conversion dispatch for ForestWrapper.

Project.toml

@@ -1,7 +1,7 @@
 name = "T8code"
 uuid = "d0cc0030-9a40-4274-8435-baadcfd54fa1"
 authors = ["Johannes Markert <[email protected]>"]
-version = "0.7.1"
+version = "0.7.2"
 
 [deps]
 CEnum = "fa961155-64e5-5f13-b03f-caf6b980ea82"

src/T8code.jl

@@ -212,6 +212,13 @@ mutable struct ForestWrapper
     end
 end
 
+Base.pointer(fw::ForestWrapper) = fw.pointer
+# This dispatched conversion allows to conveniently pass a ForestWrapper object
+# to `t8_forest_...` calls.  The following link leads to a lengthy discussion
+# about if this is a valid way to achieve this:
+# https://discourse.julialang.org/t/how-to-use-ccall-cconvert-and-unsafe-convert-in-a-convenient-and-memory-safe-way/41932/18
+Base.unsafe_convert(::Type{Ptr{t8_forest}}, fw::ForestWrapper) = fw.pointer
+
 function clean_up()
     # Finalize all registered t8code objects before MPI shuts down.
     while length(T8CODE_OBJECT_TRACKER) > 0