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Importing a C-style .dll AND marshalling confusing data types.

TheGooch
TheGooch asked
on
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Last Modified: 2012-06-27
I am using the .NET Interop services to import a .dll written in C.  One of the functions in the .dll has some very confusing data types.  I'm new to marshalling data types - anyone want to help?

//// The original C-style function declaration looks something like this:
__int32 FunctionName( void * A, const char * B, unsigned char * C, unsigned __int32 D, unsigned char ** E, unsinged __int32 * F, unsigned char ** G, unsigned __int32 * G);

//// My C# code will look something like this:
using System;
using System.Runtime.InteropServices;

namespace SomeNamespace
{
   public class SomeClass
   {
        [ DllImport( "SomeLibrary.dll" )]
        public static extern int FunctionName( ..... WHAT SHOULD I DO NEXT ????? )
   }
}

//////////
So, my question is: what C# treatment do I give all those ugly C-style data types???

Thanks!!!
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Commented:
All pointers (including **) should be passed as IntPtr.
Rwad about Marshal class. You need its functions to prepare input parameters to this function and to read output parameters.
For example, if A parameter expects pointer to some data, allocate memory block in C# using Marshal.AllocHGlobal Method. It returns IntPtr. Fill this block using unsafe programming and pass IntPtr to FunctionName.
If B points to ansi string, use Marshal.StringToHGlobalAnsi Method to allocate this string on non-managed heap and pass result IntPtr to the function.
Double pointer (**) may be passed as IntPtr ref or out parameter.
Commented:
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