According to the .NET documentation and statements posted here by others,
the non-blocking implementation of the .NET Socket class uses IOCP.  If your
goal is to use IOCP, it seems to me that using .NET is probably one of the
easiest ways to do that, since it's Socket API is fairly simple.

Implementing IOCP code in regular C++, using only Winsock and without the
assistance of 3rd-party libraries, is not only a chore, it's complex and
fraught with potential pitfalls and opportunities for errors.

If coding IOCP using plain C++ and the Win32 Winsock API is within your
capabilities, then using the async methods in the Socket class should be
trivial for you.  We're talking weeks to get it right under C++, versus a
day or so under .NET (more or less, depending on your actual capabilities as
a coder).

Full optimizations and possibly other details may take longer, of course.
I'm just talking about the basic implementation.  But that may well be
sufficient for your needs, and even if it's not, I suspect that any extra
stuff will have a similar relative cost using Win32 versus .NET.

Pete

It's not an either-or proposition.  The .NET sockets implementation uses
IOCPs for async operation and is very highly scalable - use it.

Whether you use it from C++, C# or any other .NET language is a completely
separate decision.

-cd

Ah! Don't do it. You're hurting yourself. Repeat after me: IOCP. IOCP. IOCP.

It's quicker and less bug prone to write it using IOCP in .Net, than it is
to do it using mulitple threads.

.Net. Hands down.

Then run it on x64 and really make it cool...