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

Parameters

ioControlCode

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

optionInValue

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

optionOutValue

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

Return Value

The number of bytes in the optionOutValue parameter.

Exception typeCondition

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.

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;
 }

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

static void DisplayPendingByteCount(Socket s)
{
    ubyte outValue[] = BitConverter.GetBytes(0);
    // Check how many bytes have been received.
    s.IOControl(FIONREAD, null, outValue);

    UInt32 bytesAvailable = BitConverter.ToUInt32(outValue, 0);
    //ToDo: Unsigned Integers not supported- converted to int
    Console.WriteLine("server has {0} bytes pending. Available property "
        + "says {1}.", bytesAvailable.ToString(), 
        (System.Int32)s.get_Available());
    return;
} //DisplayPendingByteCount

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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