WriteInt16 Method (IntPtr, Int32, Char)

Marshal.WriteInt16 Method (IntPtr, Int32, Char)

 

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

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

<SecurityCriticalAttribute>
Public Shared Sub WriteInt16 (
	ptr As IntPtr,
	ofs As Integer,
	val As Char
)

Parameters

ptr
Type: System.IntPtr

The base address in the native heap to write to.

ofs
Type: System.Int32

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

val
Type: System.Char

The value to write.

Exception Condition
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.

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

Sub ReadWriteInt16()
    ' Allocate unmanaged memory. 
    Dim elementSize As Integer = 2
    Dim unmanagedArray As IntPtr = Marshal.AllocHGlobal(10 * elementSize)

    ' Set the 10 elements of the C-style unmanagedArray
    For i As Integer = 0 To 9
        Marshal.WriteInt16(unmanagedArray, i * elementSize, CType(i + 1, Int16))
    Next i
    Console.WriteLine("Unmanaged memory written.")

    Console.WriteLine("Reading unmanaged memory:")
    ' Print the 10 elements of the C-style unmanagedArray
    For i As Integer = 0 To 9
        Console.WriteLine(Marshal.ReadInt16(unmanagedArray, i * elementSize))
    Next i

    Marshal.FreeHGlobal(unmanagedArray)

    Console.WriteLine("Done. Press Enter to continue.")
    Console.ReadLine()
End Sub

SecurityCriticalAttribute

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

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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