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Marshal.WriteInt16 Method (IntPtr, Int32, Char)

Writes a 16-bit signed integer value to unmanaged memory.

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

[SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
public static void WriteInt16(
	IntPtr ptr,
	int ofs,
	char val
)

Parameters

ptr
Type: System.IntPtr

The base address in the native heap to write.

ofs
Type: System.Int32

An additional byte offset, added to the ptr parameter before writing.

val
Type: System.Char

The value to write.

ExceptionCondition
AccessViolationException

Base address (ptr) plus offset byte (ofs) produces a null or invalid address.

WriteInt16 enables direct interaction with an unmanaged 16-bit signed 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.

NoteNote:

This method uses SecurityAction.LinkDemand to prevent it from being called from untrusted code; only the immediate caller is required to have SecurityPermissionAttribute.UnmanagedCode permission. If your code can be called from partially trusted code, do not pass user input to Marshal class methods without validation. For important limitations on using the LinkDemand member, see Demand vs. LinkDemand.

The following code example demonstrates how to read and write to an unmanaged array using the ReadInt16 and WriteInt16 methods.

static void ReadWriteInt16()
{
    // Allocate unmanaged memory.  
    int elementSize = 2;
    IntPtr unmanagedArray = Marshal.AllocHGlobal(10 * elementSize);

    // Set the 10 elements of the C-style unmanagedArray 
    for (int i = 0; i < 10; i++)
    {
        Marshal.WriteInt16(unmanagedArray, i * elementSize, ((Int16)(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.ReadInt16(unmanagedArray, i * elementSize));
    }

    Marshal.FreeHGlobal(unmanagedArray);

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

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