Asynchronous select() Mechanism

The WSAAsyncSelect() API allows an application to register an interest in one or many network events. This API is provided to supersede the need to do polled network I/O. Any situation in which select() or non-blocking I/O routines (such as send() and recv()) are either already used or are being considered is usually a candidate for the WSAAsyncSelect() API. When declaring interest in such condition(s), you supply a window handle to be used for notification. The corresponding window then receives message-based notification of the conditions in which you declared an interest.

WSAAsyncSelect() allows interest to be declared in the following conditions for a particular socket:

• Socket readiness for reading

• Socket readiness for writing

• Out-of-band data ready for reading

• Socket readiness for accepting incoming connection

• Completion of non-blocking connect()

• Connection closure