How to keep ReadDirectoryChangesW from missing file changes

Question

There are many posts on the internet about the ReadDirectoryChangesW API function missing files when there is a lot of file activity. Most blame the speed at which the Read

Answer 1

If the API is unreliable, then a workaround may be your only option. That of course likely involves keeping track of lastmodified and filenames. What this doesn't mean is that you need to poll when looking for changes, rather, you can use the FileSystemWatcher as a means to trigger checking.

So if you keep track of the last 50-100 times the ReadDirectoryChangesW/FSW event happened, and you see that it is being called rapidly, you can detect this and trigger the special condition to get all the files that have been changed (and set a flag to prevent future bogus FSW events temporarily) in a few seconds.

Since some people are confused in the comments about this solution, I am proposing that you should monitor how fast events are arriving from the ReadDirectoryChangesW and when they are arriving too fast, try to attempt a workaround (usually a manual sweep of a directory).