[RESOLVED] dll returns C structure with dynamic arrays, how to get data in c# ???

[Luco]

Hello

I have a DLL written in C and I am struggling with using the functions that return a structure in C#.

C Code that compiles into dll

typedef struct
{
	unsigned int Height;        //!< Height of the image in pixels.
	unsigned int Width;         //!< Width of the image in pixels.
	unsgined short ***Pixels;           
} IMAGE;

//! Creates and initializes image structure and returns pointer to new image
__declspec(dllexport) IMAGE	CreateImage(unsigned int aHeight, unsigned int aWidth);

I need to use this function in C#, this is what i tried:

public struct IMAGE
{
	int Height;
	int Width;
	short[,,] Pixels;
}

[DLLImport("IMAGE.dll")]
public static extern IMAGE CreateImage(int aHeight, int aWidth);

But when I call

IMAGE image = new IMAGE();
image = CreateImage(100,100);

I get the error: Method's type signature is not PInvoke compatible

Other functions that return plain integers work just fine. Someone please explain how I can use a structure created by DLL.

Thanks

[Luco]

Solved it .....

public struct IMAGE
{
       public Int32 Height;
       public Int32 Width;
       public IntPtr Pixels;
}

[DllImport("Image.dll")]
public static extern IMAGE CreateImage(Uint32 Height, Uint32 Width);

after calling the CreateImage function I can use Marshal.ReadIntPrt(Pixels) and Marshal.ReadInt16(IntPtr) to get the data .