C# Signature:

[DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]
public static extern IntPtr memcpy(IntPtr dest, IntPtr src, UIntPtr count);

VB.NET Signature:

    <DllImport("msvcrt.dll", EntryPoint:="memcpy", CallingConvention:=CallingConvention.Cdecl)> _
    Public Shared Sub CopyMemory(ByVal dest As IntPtr, ByVal src As IntPtr, ByVal count As Integer)
    End Sub

VB Signature:

Declare Function memcpy Lib "msvcrt.dll" ( _
     ByVal dest As Any, _
     ByVal src As Any, _
     ByVal count As Long) _
     as Long
Declare Function memcpy Lib "msvcrt.dll" (TODO) As TODO

Return Value:

The value of dest.

User-Defined Types:

None.

Alternative Managed API:

System.Buffer.BlockCopy, Marshal.Copy and Array.Copy provide similar services, but require one or two managed arrays instead of pointers.

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code VB.Net:

    Imports System.Runtime.InteropServices

    Sub Main()
    Dim managedArray1 As Char() = ("Ciao").ToCharArray
    Dim size As Integer = Marshal.SizeOf(managedArray1(0)) * managedArray1.Length
    Dim pnt1 As IntPtr = Marshal.AllocHGlobal(size)
    Dim pnt2 As IntPtr = Marshal.AllocHGlobal(size)
    Dim managedArray2(managedArray1.Length - 1) As Char
    Try
        Marshal.Copy(managedArray1, 0, pnt1, managedArray1.Length)
        '----MemCpy
        CopyMemory(pnt2, pnt1, size * 2)
        '----
        Marshal.Copy(pnt2, managedArray2, 0, managedArray2.Length)
    Finally
        Marshal.FreeHGlobal(pnt1)
        Marshal.FreeHGlobal(pnt2)
    End Try
    Dim value As String = New String(managedArray2)
    Console.WriteLine(">>" + value + "<<")

    End Sub

Sample Code C#:

    public static Bitmap Clone(Bitmap src)
    {
        // get source image size
        int width = src.Width;
        int height = src.Height;

        // lock source bitmap data
        BitmapData srcData = src.LockBits(
        new Rectangle(0, 0, width, height),
        ImageLockMode.ReadWrite, src.PixelFormat);

        // create new image
        Bitmap dst = new Bitmap(width, height, src.PixelFormat);

        // lock destination bitmap data
        BitmapData dstData = dst.LockBits(
        new Rectangle(0, 0, width, height),
        ImageLockMode.ReadWrite, dst.PixelFormat);

        memcpy(dstData.Scan0, srcData.Scan0, new UIntPtr((uint)height * (uint)srcData.Stride));

        // unlock both images
        dst.UnlockBits(dstData);
        src.UnlockBits(srcData);        

        return dst;
    }

Please edit this page!

Do you have...

• helpful tips or sample code to share for using this API in managed code?
• corrections to the existing content?
• variations of the signature you want to share?
• additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).