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IntPtr.Subtract Method

Subtracts an offset from the value of a pointer.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
public static IntPtr Subtract(
	IntPtr pointer,
	int offset
)

Parameters

pointer
Type: System.IntPtr

The pointer to subtract the offset from.

offset
Type: System.Int32

The offset to subtract.

Return Value

Type: System.IntPtr
A new pointer that reflects the subtraction of offset from pointer.

The Subtract method does not throw an exception if the result is too small to represent as a pointer on the specified platform. Instead, the subtraction operation is performed in an unchecked context.

Languages that do not support operator overloading or custom operators can use this method to subtract an offset from the value of a pointer.

The following example instantiates an IntPtr object that points to the end of a ten-element array, and then calls the Subtract method to iterate the elements in the array in reverse order.

using System;

public class Example
{
   public static void Main()
   {
      int[] arr = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
      IntPtr ptr = (IntPtr) arr[arr.GetUpperBound(0)];
      for (int ctr = 0; ctr <= arr.GetUpperBound(0); ctr++)
      {
         IntPtr newPtr = IntPtr.Subtract(ptr, ctr);
         Console.Write("{0}   ", newPtr);
      }
   }
}
// The example displays the following output: 
//       10   9   8   7   6   5   4   3   2   1

.NET Framework

Supported in: 4.5.1, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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