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Socket.DuplicateAndClose Method

Duplicates the socket reference for the target process, and closes the socket for this process.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)

public SocketInformation DuplicateAndClose(
	int targetProcessId


Type: System.Int32
The ID of the target process where a duplicate of the socket reference is created.

Return Value

Type: System.Net.Sockets.SocketInformation
The socket reference to be passed to the target process.


targetProcessID is not a valid process id.


Duplication of the socket reference failed.

The target process should use Socket to create the duplicate socket instance.

If you call the Socket constructor multiple times with the same byte array as the argument for each call, you will create multiple managed Socket instances with the same underlying socket. This practice is strongly discouraged.

If the process creating the socket uses asynchronous methods (BeginReceive or BeginSend), the process must first set the UseOnlyOverlappedIO property to true; otherwise, the socket is bound to the completion port of the creating process, which may cause an ArgumentNullException to be thrown on the target process.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.