I'm not an expert, but I think you're right for POSIX.
Windows does apparently offer the necessary building blocks; this is the most relevant HN sub-discussion: https://news.ycombinator.com/item?id=9584269
Windows does apparently offer the necessary building blocks; this is the most relevant HN sub-discussion: https://news.ycombinator.com/item?id=9584269
https://lwn.net/Articles/724198/ (May 30, 2017)
In truth, an AIO operation can block in the kernel for a number of reasons, making AIO difficult to use in situations where the calling thread truly cannot afford to block. A longstanding patch set aiming to improve this situation would appear to be nearing completion, but it is more of a step in the right direction than a true solution to the problem.
In other words, AIO seems likely to remain useful only for the handful of applications that perform direct I/O to files.
If it works in the sense that the kernel supports the API and implements aoi internally using async mechanisms, then that would be awesome. Is that the case?