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IntPtr.Add(IntPtr, Int32) Method

  • Reference

Definition

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

Adds an offset to a signed integer.

public:
 static IntPtr Add(IntPtr pointer, int offset);
public static IntPtr Add (IntPtr pointer, int offset);
static member Add : nativeint * int -> nativeint
Public Shared Function Add (pointer As IntPtr, offset As Integer) As IntPtr

Parameters

pointer
IntPtr

nativeint

The signed integer to add the offset to.

offset
Int32

The offset to add.

Returns

IntPtr

nativeint

A new signed integer that reflects the addition of offset to pointer.

Examples

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

using System;
using System.Runtime.InteropServices;

public class Example
{
   public static void Main()
   {
      int[] arr = { 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 };
      unsafe {
         fixed(int* parr = arr) {
            IntPtr ptr = new IntPtr(parr);
            // Get the size of an array element.
            int size = sizeof(int);
            for (int ctr = 0; ctr < arr.Length; ctr++)
            {
               IntPtr newPtr = IntPtr.Add(ptr, ctr * size);
               Console.Write("{0}   ", Marshal.ReadInt32(newPtr));
            }
         }
      }
   }
}
// The example displays the following output:
//       2   4   6   8   10   12   14   16   18   20

#nowarn "9"
open System
open System.Runtime.InteropServices
open FSharp.NativeInterop

[<EntryPoint>]
let main _ =
    let mutable arr = 
        [| 2; 4; 6; 8; 10; 12; 14; 16; 18; 20 |]
    
    use parr = fixed arr
    
    let ptr = NativePtr.toNativeInt parr

    // Get the size of an array element.
    let size = sizeof<int>
    for i = 0 to arr.Length - 1 do
        let newPtr = IntPtr.Add(ptr, i * size)
        printf $"{Marshal.ReadInt32 newPtr}   "
    0

// The example displays the following output:
//       2   4   6   8   10   12   14   16   18   20

Imports System.Runtime.InteropServices

Module Example
   Public Sub Main()
      Dim arr() As Integer = { 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 }
      Dim ptr As IntPtr = Marshal.UnsafeAddrOfPinnedArrayElement(arr, 0)

      For ctr As Integer= 0 To arr.Length - 1
         Dim newPtr As IntPtr = IntPtr.Add(ptr, ctr * Len(arr(0)))
         Console.Write("{0}   ", Marshal.ReadInt32(newPtr))
      Next
   End Sub
End Module
' The example displays the following output:
'       2   4   6   8   10   12   14   16   18   20

Remarks

The Add method does not throw an exception if the result is too large to represent as a signed integer in the executing process. Instead, the addition operation is performed in an unchecked context.

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

Applies to

See also