C# DLLimport function returning an array of pointer to structures

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Hello,

I need to call a function which returns an array of pointer to structures :

here is the c++ declaration :

C++

const VDXPluginInfo *const *VDXAPIENTRY VDGetPluginInfo();

it returns an array of pointers to a VDXAPIENTRY, which is terminated by a pointer to zero

How can I translate this to call it from c# ?

Of course, I searched the web, and found many things about pointer arrays in arguments, but never returned from function.

Thank you.

Posted 19-May-12 10:18am

Kitarolivier

Updated 19-May-12 21:21pm

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OriginalGriff 20-May-12 3:29am

Don't bump your question - it's rude. Especially when it was only half way down the unanswered page...

Kitarolivier 20-May-12 11:50am

I didn't bump my question, I just edited to add more description. Sorry.

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Mark Kruger · Accepted Answer · 2012-05-25T03:16:00

I Guess i would try something as the next, couldn't check if it worked though, i've nothin' alike.

C#

[DllImport("**YOURDLL**"]
private static extern int VDGetPluginInfo();

[StructLayout(LayoutKind.Sequential)]
private struct VDPointer
{
    public int VDXPlugin;
}

public List<intptr> GetPointers()
{
   VDPointer Result = new VDPointer();
   Result.VDXPlugin = -1; //we want our first run to go
   List<intptr> ToFill = new List<intptr>();
   int Retrieve = VDGetPluginInfo; //We should have gotten start adres of the array on our int
   
   while (Result. VDXPlugin != 0)
   {
      Result = (VDPointer)Marshal.PtrToStructure(new IntPtr(Retrieve), typeof(VDPointer));
      if (Result.VDXPlugin != 0)
      {
          Retrieve += 4; //Let's step to next pointer entry, assuming pointer is 32 bit int
          ToFill.Add(new IntPtr(Result.VDXPlugin));
      }
   }

   return ToFill;
}

I think this should do the trick, and from there u could retrieve the contents of the pointers the same:

C#

VDXPluginInfo GetMe = (VDXPluginInfo)Marshal.PtrToStructure(List[0], typeof(VDXPluginInfo)); //etc etc