WSARecvDisconnect function (winsock2.h)

Article
10/13/2021

The WSARecvDisconnect function terminates reception on a socket, and retrieves the disconnect data if the socket is connection oriented.

Syntax

int WSAAPI WSARecvDisconnect(
  [in]  SOCKET   s,
  [out] LPWSABUF lpInboundDisconnectData
);

Parameters

[in] s

A descriptor identifying a socket.

[out] lpInboundDisconnectData

A pointer to the incoming disconnect data.

Return value

If no error occurs, WSARecvDisconnect returns zero. Otherwise, a value of SOCKET_ERROR is returned, and a specific error code can be retrieved by calling WSAGetLastError.

Error code	Meaning
WSANOTINITIALISED	A successful WSAStartup call must occur before using this function.
WSAENETDOWN	The network subsystem has failed.
WSAEFAULT	The buffer referenced by the parameter lpInboundDisconnectData is too small.
WSAENOPROTOOPT	The disconnect data is not supported by the indicated protocol family. Note that implementations of TCP/IP that do not support disconnect data are not required to return the WSAENOPROTOOPT error code. See the remarks section for information about the Microsoft implementation of TCP/IP.
WSAEINPROGRESS	A blocking Windows Sockets 1.1 call is in progress, or the service provider is still processing a callback function.
WSAENOTCONN	The socket is not connected (connection-oriented sockets only).
WSAENOTSOCK	The descriptor is not a socket.

Remarks

The WSARecvDisconnect function is used on connection-oriented sockets to disable reception and retrieve any incoming disconnect data from the remote party. This is equivalent to a shutdown (SD_RECEIVE), except that WSARecvDisconnect also allows receipt of disconnect data (in protocols that support it).

After this function has been successfully issued, subsequent receives on the socket will be disallowed. Calling WSARecvDisconnect has no effect on the lower protocol layers. For TCP sockets, if there is still data queued on the socket waiting to be received, or data arrives subsequently, the connection is reset, since the data cannot be delivered to the user. For UDP, incoming datagrams are accepted and queued. In no case will an ICMP error packet be generated.

Note The native implementation of TCP/IP on Windows does not support disconnect data. Disconnect data is only supported with Windows Sockets providers that have the XP1_DISCONNECT_DATA flag in their WSAPROTOCOL_INFO structure. Use the WSAEnumProtocols function to obtain WSAPROTOCOL_INFO structures for all installed providers.

To successfully receive incoming disconnect data, an application must use other mechanisms to determine that the circuit has been closed. For example, an application needs to receive an FD_CLOSE notification, to receive a zero return value, or to receive a WSAEDISCON or WSAECONNRESET error code from recv/WSARecv.

The WSARecvDisconnect function does not close the socket, and resources attached to the socket will not be freed until closesocket is invoked.

The WSARecvDisconnect function does not block regardless of the SO_LINGER setting on the socket.

An application should not rely on being able to reuse a socket after it has been disconnected using WSARecvDisconnect. In particular, a Windows Sockets provider is not required to support the use of connect or WSAConnect on such a socket.

Note When issuing a blocking Winsock call such as WSARecvDisconnect, Winsock may need to wait for a network event before the call can complete. Winsock performs an alertable wait in this situation, which can be interrupted by an asynchronous procedure call (APC) scheduled on the same thread. Issuing another blocking Winsock call inside an APC that interrupted an ongoing blocking Winsock call on the same thread will lead to undefined behavior, and must never be attempted by Winsock clients.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	winsock2.h
Library	Ws2_32.lib
DLL	Ws2_32.dll