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UIntPtr.Subtract(UIntPtr, Int32) Method

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Definition

Namespace:
System
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Source:
UIntPtr.cs
Source:
UIntPtr.cs
Source:
UIntPtr.cs

Subtracts an offset from an unsigned integer.

public:
 static UIntPtr Subtract(UIntPtr pointer, int offset);
public static UIntPtr Subtract (UIntPtr pointer, int offset);
static member Subtract : unativeint * int -> unativeint
Public Shared Function Subtract (pointer As UIntPtr, offset As Integer) As UIntPtr

Parameters

pointer
UIntPtr

unativeint

The unsigned integer to subtract the offset from.

offset
Int32

The offset to subtract.

Returns

UIntPtr

unativeint

A new unsigned integer that reflects the subtraction of offset from pointer.

Examples

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

open System

let arr = [| 1; 2; 3; 4; 5; 6; 7; 8; 9; 10 |]
let ptr = UIntPtr(uint arr[arr.GetUpperBound 0])
for i = 0 to arr.GetUpperBound 0 do
    let newPtr = UIntPtr.Subtract(ptr, i)
    printf $"{newPtr}   "
// The example displays the following output:
//       10   9   8   7   6   5   4   3   2   1

Module Example
   Public Sub Main()
      Dim arr() As Integer = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
      Dim ptr As UIntPtr = CType(arr(arr.GetUpperBound(0)), UIntPtr)
      For ctr As Integer= 0 To arr.GetUpperBound(0)
         Dim newPtr As UIntPtr = UIntPtr.Subtract(ptr, ctr)
         Console.Write("{0}   ", newPtr)
      Next
   End Sub
End Module
' The example displays the following output:
'       10   9   8   7   6   5   4   3   2   1

Remarks

The Subtract method does not throw an exception if the result is too small to represent as an unsigned integer in the executing process. 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.

Applies to

See also