Microsoft KB Archive/181610

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INFO: WSA_FLAG_OVERLAPPED Needed for Timeout on WSASocket

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Q181610

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The information in this article applies to:


 * Microsoft Win32 Software Development Kit (SDK), used with:
 * the operating system: Microsoft Windows NT
 * Microsoft Windows 95
 * Microsoft Windows 98
 * the operating system: Microsoft Windows 2000

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SUMMARY
If you create a socket using the Winsock 2 WSASocket API and you need to apply a timeout in receive or send operations on the socket, you must specify the WSA_FLAG_OVERLAPPED flag in the WSASocket call.

MORE INFORMATION
If a socket is created without the overlapped I/O attribute, all I/O operations on the socket are synchronous. So if your program has set socket options SO_SNDTIMEO and SO_RCVTIMEO, you need to make sure your socket is created with the overlapped I/O attribute to timeout your blocking send or receive operations.

The overlapped I/O attribute of a socket created via the socket API is set internally. If you use WSASocket API, you need to set the WSA_FLAG_OVERLAPPED flag yourself in the last parameter of this API call.

Additional query words:

Keywords : kbnetwork kbAPI kbOSWinNT400 kbOSWin2000 kbSDKPlatform kbOSWin95 kbOSWin98 kbWinsock kbGrpDSNet

Issue type : kbinfo

Technology : kbWin32SDKSearch kbAudDeveloper kbSDKSearch kbWin32sSearch