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IOControl Method (Int32, Byte[], Byte[])
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Socket.IOControl Method (Int32, Byte[], Byte[])

Sets low-level operating modes for the Socket using numerical control codes.

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

public int IOControl(
	int ioControlCode,
	byte[] optionInValue,
	byte[] optionOutValue
)

Parameters

ioControlCode
Type: System.Int32

An Int32 value that specifies the control code of the operation to perform.

optionInValue
Type: System.Byte[]

A Byte array that contains the input data required by the operation.

optionOutValue
Type: System.Byte[]

A Byte array that contains the output data returned by the operation.

Return Value

Type: System.Int32
The number of bytes in the optionOutValue parameter.

ExceptionCondition
SocketException

An error occurred when attempting to access the socket. See the Remarks section for more information.

ObjectDisposedException

The Socket has been closed.

InvalidOperationException

An attempt was made to change the blocking mode without using the Blocking property.

SecurityException

A caller in the call stack does not have the required permissions.

The IOControl method provides low-level access to the operating system Socket underlying the current instance of the Socket class. For more information, see the WSAIoctl documentation in the MSDN library.

NoteNote

If you receive a SocketException, use the SocketException.ErrorCode property to obtain the specific error code. After you have obtained this code, refer to the Windows Sockets version 2 API error code documentation in the MSDN library for a detailed description of the error.

NoteNote

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.

The following code example compares the results of FIONREAD and the Available property.

 // FIONREAD is also available as the "Available" property.
public const int FIONREAD   = 0x4004667F;

static void DisplayPendingByteCount(Socket s)
 {
     byte[] outValue = BitConverter.GetBytes(0);

     // Check how many bytes have been received.
     s.IOControl(FIONREAD, null, outValue);

     uint bytesAvailable = BitConverter.ToUInt32(outValue, 0);
     Console.WriteLine("server has {0} bytes pending. Available property says {1}.",
         bytesAvailable, s.Available);

     return;
 }

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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