Knowledge Base

FIX: FD_WRITE Reposted After Every Send

Article ID: 186245

Article Last Modified on 9/23/2005


APPLIES TO


This article was previously published under Q186245

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

This problem was corrected in Windows 2000.

Keywords: kbbug kbfix kbwinsock kbapi kbqfe kbnetwork kboswin2000fix kbhotfixserver KB186245