<p>What is Windows' best I/O event notification facility? </p>

<p>By best I mean something that ...</p>

<ol>
<li>doesn't have a limit on number of input file descriptors</li>
<li>works on all file descriptors (disk files, sockets, ...)</li>
<li>provides various notification modes (edge triggered, limit triggered)</li>
</ol>

There isn't one yet, as far as I am aware.  A friend and I are working on an open source Windows epoll implementation (link below) but we're running into issues figuring out how to make it act the same as the Linux implementation.
Current obstacles:
In Linux, file descriptors and socket descriptors are interchangeable, but in Windows they are not.  Both must be compatible with an epoll implementation.
In Windows it's quite tricky to get kernel events...  which is how epoll works in Linux.  We're guessing that a program using our cross-platform epoll library will run noticeably slower in Windows than Linux.
I'll try to come back and update this post as we make progress with the project.
http://sourceforge.net/projects/cpoll