BUG: FD_WRITE Reposted After Every Send

• Microsoft Windows NT 4.0

SYMPTOMS

When developing a Winsock application using WSAAsyncSelect or WSAEventSelect, the FD_WRITE notification is delivered after every call to send and WSASend on the Windows NT 4.0 platform (up through and including Service Pack 3), even if the call did not fail with the error code WSAEWOULDBLOCK. This behavior is not according to the Winsock specification, and applications should not rely on it.

RESOLUTION

If your application indicates interest in receiving FD_WRITE notification, using either WSAAsyncSelect or WSAEventSelect, your application should continue to send data (send and WSASend) until WSAEWOULDBLOCK is returned. If your applications stops sending data before receiving this error code and relies on FD_WRITE subsequently being delivered, it will not run properly across all Windows platforms.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

Additional query words:

Keywords : kbnetwork kbAPI kbNTOS400bug kbSDKPlatform kbWinsock kbGrpNet
Version : winnt:4.0
Platform : winnt
Issue type : kbbug