Re: WSAyncSelect in Multithreading

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>
Sun, 13 Aug 2006 15:09:35 -0400
Phanidhar wrote:

Thanks for the response.

 I'm just wondering how re-entry is possible? Isn't message loop (like
GetMessage() ) supposed to be synchronized? Is this behaviour only in
asynchronous socket notification? How abt this in other cases where any event
notification is involved. Can you point to me to any documents/links
available on net so that I can gain more claruty on this

Sychronization is not the issue. Messages will only be received when
you call GetMessage, or you call code that calls GetMessage. If a
message is waiting then you will get it. This is "synchronous reentry."
  It does not matter whether you call from some other message handler.

This is common in all windows programs and not unique to socket
messages. What you have done is reenter the message loop from another
message handler so, naturally, the wndProc can then reenter. Example:

What is unique about the socket notification message is that it is the
same message, addressed to the sanme window, as the message you are
already handling. Hopefully, the Win32 API does not have other cases
like this!

Scott McPhillips [VC++ MVP]

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