mortoray/quantlib — comment on commit dbf6b23429b21cccb0982d6f3e5c13f5860842e1
File: ql/patterns/singleton.hpp line 95
By lballabio:

Do you have any use case in mind in which `create()` should not use `new`?
Also, right now there's no way to pass another function to `SingletonInstanceLoader` (since it can't be passed to the `instance()` method which calls it) and `create()` is not virtual, so it can't be overridden. So we end up always using `new` anyway.