C# control the alignment of data

Question

In C++ you can use __declspec( align( # ) ) declarator to control the alignment of user-defined data. How can do this for C#. I have two procedures written on Assembler in my dll. Arguments for procedures (two arrays) should be aligned on 16 bytes. For C++ it works fine.

I just used declarations

__declspec( align( 16 ) )
double a[2]={10.2,10.6};

Answer 1

If you are looking for managed to non-managed interop (transmitting data between C#/.NET-based and C/C++/assembler-based software), you would use a combination of the StructLayout attribute and the FieldOffset attribute:

[StructLayout(LayoutKind.Explicit, Pack = 16)]
public class MyDataClass {
    [FieldOffset(0)]
    double[] a;
}

According to MSDN:

The System.Runtime.InteropServices.StructLayoutAttribute.Pack field determines the memory alignment of data fields of a target object.

http://support.microsoft.com/kb/922785