[MOAB-dev] Order of elements in loaded meshes

[Steve Jackson]

When MOAB loads a mesh file, the mesh elements have a certain order in EntityHandle space.  I'd like to know how reliable/repeatable this ordering is.  (Note I'm asking about the order of handles, not their specific values.)  

For a given mesh file, what guarantees do I get about the order of EntityHandles...

* ...between separate runs of the same program?  (i.e. May I assume the order of entity handles will be the same every time MOAB loads a file?)

* ...between runs of two different programs using the same MOAB library?  (Does the order of entities loaded from a file depend on the program that is calling MOAB?)

* ...between runs of two programs using different versions of MOAB?  (Does the order of entities depend on changes to MOAB, even if those changes do not affect the specific file reader that loads the mesh?)

What I am looking for is a way to consistently refer to "the 1st/2nd/nth tetrahedron" in a given file, preferably without resorting to tags.
~S