@whitequark @wingo Also, there is something to be said for programming against a single implementation whose behaviour is, in doubt, observable; especially on a platform like Windows which (historically at least) goes to great lengths to never break any observed behaviours; compared to POSIX which so often just shrugs and lets implementations do whatever …
(And I obviously say that as someone who works on a specification with many implementations which also just shrugs and underspecifies a lot)