Hi, Sorry, I am a GMail user, so I am unable to reply to the original email from Eric Blake ebl...@redhat.com on Thu May 3 14:03:00 GMT 2018: https://cygwin.com/pipermail/cygwin/2018-May/237069.html
Eric wrote: <<And patches to make Cygwin support inotify_init() and friends implemented on top of the Windows native API are certainly welcome.>> First, please correct me if Linux-style inotify is already supported in Cygwin. As I understand, it is not. To be clear, when I say "inotify", I mean this Linux kernel API: https://man7.org/linux/man-pages/man7/inotify.7.html Second, I am interested in exploring this feature as a personal project. After some research, I found two different solutions on Windows: 1. FindNextChangeNotification() and friends explained here: https://learn.microsoft.com/en-us/windows/win32/fileio/obtaining-directory-change-notifications 2. (NTFS) Change Journals explained here: https://learn.microsoft.com/en-us/windows/win32/fileio/change-journals There is some discussion about both approaches on StackOverflow.com here: https://stackoverflow.com/questions/3517460/is-there-anything-like-inotify-on-windows In short, it sounds like #1 (above) is unreliable and can drop/miss file system events if too fast and/or the kernel notification queue is full/overloaded. However, #2 (above) requires journalling to be enabled on an NTFS volume. And, it sounds like this feature is *only* available on NTFS volumes. (FAT/32 & friends would need to use #1.) My thoughts & concerns: - #1 might be easier to program but if dropped events are a reality, then ... meh, not such a great feature! - #2 is restricted to NTFS, but sounds very reliable ("rock solid", one person said). However, journalling needs to be enabled. I guess the inotify API can just return an error if journaling is disabled for an NTFS volume. And, I see two solutions for non-NTFS volumes: inotify API returns error, or fall-back to #2. More: It sounds like journaling might be disabled by default. - https://stackoverflow.com/questions/27184283/is-the-usn-journal-disabled-by-default - https://devblogs.microsoft.com/oldnewthing/20130101-00/?p=5673 And enabling probably requires local admin access. Maybe some kind of flag can choose #1 or #2? I would appreciate it if people could share their thoughts and advice. The Linux inotify API is an excellent feature. I have used it a few times with great success. It would be nice to have this feature on Cygwin. Kind regards, Kevin ARPE Tokyo, Japan https://github.com/kevinarpe -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
