Passing a pointer to an array to an external function

Question

I want to use lcms2.DLL library from C#.

At the time of calling the DLL function, which convert pixels data, I get an AccessViolation error.

 

I need to pass two pointers to the function, a pointer to an inputBuffer and a pointer to an outputBuffer which I have defined as Byte[].

 

This is the DLLimport :

 

[DllImport(@lcms2Path)]
public static extern void cmsDoTransform(
[In] IntPtr xform,
[In] byte[] InputBuffer,
[Out] byte[] OutputBuffer,
[In] UInt32 Size);

 

And this is my method call:

// 1 -- read an image into BitmapFrame 

BitmapFrame myBitmapFrame = decoder.Frames[0];

 

// 2 -- copy image data to inputBuffer byte array 
Byte[] inputBitmapData = new Byte[stride * myBitmapFrame.PixelHeight];           
BitmapFrame.CopyPixels(inputBitmapData, stride, 0);

 

// 3 -- duplicate inputBuffer to outputBuffer

Byte[] outputBitmapData = inputBitmapData.Clone() as Byte[];

// 4 -- Calculate number of pixels to pass 

uint pixels = (uint)myBitmapFrame.Width * (uint)myBitmapFrame.Height;

// 5 -- Call the function 

cmsDoTransform(xform, inputBitmapData, outputBitmapData, pixels);