I have a log file being written by another process which I want to watch for changes. Each time a change occurs I\'d like to read the new data in to do some processing on it
As you can see in Tim Golden's article, pointed by Horst Gutmann, WIN32 is relatively complex and watches directories, not a single file.
I'd like to suggest you look into IronPython, which is a .NET python implementation. With IronPython you can use all the .NET functionality - including
System.IO.FileSystemWatcher
Which handles single files with a simple Event interface.