On Nov 23 23:36, Cedric Blancher via Cygwin wrote: > Linux has fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, ...) > to punch a hole into a file, i.e. deallocate the blocks given and make > the file a "sparse file".
We don't support the Linux-specific fallocate(2) call, only ftruncate(2) and posix_fallocate(3). Patches, as usual, thoughtfully considered. > But how can I do that with the Cygwin API? Does anyone have an example > for Cygwin, which is the Win equivalent to Linux fallocate(fd, > FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 1048576, 2097152);? > > I tried with Cygwin 3.5, but the file was not sparse after that. Do you remember the discussion in August, starting here: https://cygwin.com/pipermail/cygwin-developers/2023-August/012664.html especially: https://cygwin.com/pipermail/cygwin-developers/2023-August/012679.html So, did you set the sparse mount option per https://cygwin.com/cygwin-ug-net/using.html#mount-table ? Also, chattr -S, which is independent from the mount option "sparse": https://cygwin.com/cygwin-ug-net/chattr.html Corinna -- 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
