I think that particular pattern is a perfectly reasonable way to let the user ingest an arbitrarily long list of objects without having to do any preallocations -- or indeed, any allocations at all.
Because allocating well under a hundred handles is a biggest problem we have.
WinAPI is awful to work with for reasons above anyone’s comprehension. It’s just legacy riding on legacy, with initial legacy made by someone 50% following stupid patterns from the previous 8/16 bit decade and 50% high on mushrooms. The first thing you do with WinAPI is abstracting it tf away from your face.
Which is a pattern that also exists in the Win32 API, for example in the handle = CreateToolhelp32Snapshot(), Thread32First(handle, out), while Thread32Next(handle, out) API for iterating over a process's threads.
I also find EnumChildWindows pretty wacky. It's not too bad to use, but it's a weird pattern and a pattern that Windows has also moved away from since XP.
