I was looking recently for a solution to a somewhat different problem, also on Win2k: read from socket with timeout (so that my client does not block forever when the server does not respond, for whatever reason).

I found a working solution based on IO::Select. Using the 4-arg select() or the module IO::Select is often mentioned in discussion groups. I found a very helpful discussion with many examples in Sriram Srinivasan's Advanced Perl Programming (the Black Panther book), chapter 12, Networking with Sockets.

The section "Multiplexing Using select" (page 195-) seems to be close to what you need. In this approach, you don't make the socket non-blocking but you call IO::Select->select() to return you a list of sockets that have something ready to be read.

HTH

Rudif

Update: I just received a copy of Lincoln D.Stein's book 'Network Programming with Perl' - I would add 'Fully Explained', from my first impressions. It has a whole chapter (13) on Non-blocking I/O that might interest you.

The subject matter is somewhat UNIX-centric, but the author discusses the cross-platform portability (mainly Windows and Mac) in many places. Even so, in my first attempt to run an example from Chapter 13 I had a minor portability problem on Win2k, which I could solve by replacing  use Errno 'EINPROGRESS'; by  use POSIX qw(:errno_h);