Marshal.WriteIntPtr Method (IntPtr, IntPtr)


Writes a processor native sized integer value into unmanaged memory.

Namespace:   System.Runtime.InteropServices
Assembly:  mscorlib (in mscorlib.dll)

public static void WriteIntPtr(
	IntPtr ptr,
	IntPtr val


Type: System.IntPtr

The address in unmanaged memory to write to.

Type: System.IntPtr

The value to write.

Exception Condition

ptr is not a recognized format.


ptr is null.


ptr is invalid.

WriteIntPtr enables direct interaction with an unmanaged C-style IntPtr array, eliminating the expense of copying an entire unmanaged array (using Marshal.Copy) to a separate managed array before setting its element values.

Writing to unaligned memory locations is supported.

The following example demonstrates how to read and write to an unmanaged array using the ReadIntPtr and WriteIntPtr methods.

static void ReadWriteIntPtr()
    // Allocate unmanaged memory. 
    int elementSize = Marshal.SizeOf(typeof(IntPtr));
    IntPtr unmanagedArray = Marshal.AllocHGlobal(10 * elementSize);

    // Set the 10 elements of the C-style unmanagedArray
    for (int i = 0; i < 10; i++)
        Marshal.WriteIntPtr(unmanagedArray, i * elementSize, ((IntPtr)(i + 1)));
    Console.WriteLine("Unmanaged memory written.");

    Console.WriteLine("Reading unmanaged memory:");
    // Print the 10 elements of the C-style unmanagedArray
    for (int i = 0; i < 10; i++)
        Console.WriteLine(Marshal.ReadIntPtr(unmanagedArray, i * elementSize));


    Console.WriteLine("Done. Press Enter to continue.");


requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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