Is is possible to use IOCP (or other API) in Reactor-style operations?

Is there any scalable Win32 API (like IOCP not like select) that gives you reactor style operations on so开发者_高级运维ckets? AFAIK IOCP allows you to receive notification on completed operations like data read or written (proactor) but I'm looking for reactor style of operations: I need to get notification when the socket is readable or writable (reactor).

Something similar to epoll, kqueue, /dev/poll ?

Is there such API in Win32? If so where can I find a manual on it?

** Clarification:** I need select like api for sockets that is as scalable as IOCP, or I'm looking for a way to use IOCP in reactor like operations.

Even more clarification: IOCP allows you to receive an notification on completion of given operation. For example:

WSARecv(buffer,...); // start reading
WSAWaitForMultipleEvents(...); // wait when read is done

So I get notication after operation is done -- proctor style of operations.

What I need is something like that:

WSARecv( NOTHING ); // start waiting for readability (not actual read)
WSAWaitForMultipleEvents(...); // wait until read would not block
// Now WSARecv would not block
WSARecv(buffer,...); // now actual non-blocking read

How can I do this?

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You want to look at the WSAAsyncSelect API. It uses a Windows message queue to signal that a handle is read for read/write/whatever, so it doesn't have the concurrency benefits of IOCP, but it allows you to implement a standard reactor pattern without having a limit to the number of handles (like WSAWaitForMultipleEvents).

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I'm confused, isn't Reactor pattern where the thread blocks waiting on multiple event sources? That would be select(), which windows supports. The Proactor pattern is where there is a single callback per call, that you can do via ReadFileEx/WriteFileEx.

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Not possible.

I've checked Boost.Asio sources that do have reactor style operations and use IOCP. For all reactor style operations separate thread with select is used instead of IOCP.

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Have you tried passing zero nNumberOfBytesToRead to, for example ReadFile(socket_fd, ..)?

Maybe it will help to get the "read ready" event.