Since QFileSystemWatcher is very basic (because it is supposed to be platform-independent) I wrote a very simple layer for Fam. It's probably full of bugs and disrespects one of the main goals of Qt, that is Platform-independence. It may however be useful to some users that don't need platform-independence. It should work on all Unixes that support Fam/Gamin. I tested it on linux. The respective files that you should include in your project are:

filesystemwatcher.cpp
filesystemwatcher.h
filesystemevent.cpp
filesystemevent.h


FileSystemWatcher looks a little like QFileSystemWatcher. It has the same accessor functions to add files to be monitored and remove them again. It emits the same signals as QFileSystemWatcher would do, namely:
fileChanged(const QString&), directoryChanged(const QString&). Furthermore it emits an additional signal that provides a FileSystemEvent object that can be used to query details about what was going on.

I've provided a simple test application filemonitor.jpg to test the classes. The classes are only a few days old, lack documentation, probably contain plenty of bugs and is still somewhat inconsistent with QFileSystemWatchers behaviour. For Instance, deleting a monitored file does not remove it from fam/gamin. so when it gets recreated it is still watched. I'll probably change that soon though.

It'd be nice if someone could give me some feedback about it

The tarball containing both test application and the classes can be fetched from here:
http://www.informatik.uni-bremen.de/~momesana/fam-qt.tar.bz2

Thanx in advance
momesana