Messages in this thread | | | Date | Wed, 11 May 2016 17:09:59 +0200 | From | Felix von Leitner <> | Subject | Re: getting mysterious (to me) EINVAL from inotify_rm_watch |
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Thus spake Peter Meerwald-Stadler (pmeerw@pmeerw.net): > > I am trying to add inotify support to my tail implementation (for -F). > > This is what happens: > > > > inotify_init() = 4 > > inotify_add_watch(4, "/tmp/foo", IN_MODIFY) = 1 > > inotify_rm_watch(4, 1) = -1 EINVAL (Invalid argument) > > inotify_add_watch(4, "/tmp/foo", IN_MODIFY) = 2 > > > > There is also some polling, some reading and some statting going on here, but > > those are on other descriptors than 4 so they should not matter). > > > > Can somebody explain the EINVAL I'm getting from inotify_rm_watch to me? > > This is a stock kernel 4.5.0.
> #include <stdio.h> > #include <sys/inotify.h> > int main() { > int fd, i, j; > printf("init %d\n", fd=inotify_init()); // 3 > printf("add %d\n", i=inotify_add_watch(fd, "/tmp/foo", IN_MODIFY)); // 1 > printf("rm %d\n", inotify_rm_watch(fd, i)); // 0 > printf("add %d\n", j=inotify_add_watch(fd, "/tmp/foo", IN_MODIFY)); // 2 > return 0; > }
> Ubuntu kernel x86_64 4.4.0-21, seems to work here > so we have to guess what's going on between _add and _rm?
Oh, it turns out to be my fault. I called close() on the file first, then did inotify_rm_watch.
It was not clear to me from the documentation that that automatically removes the inotify watch.
Sorry for the noise,
Felix
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