delphi LabView DLL creates weird double array

[Snieres 0]

I have a type LabView created DLL that creates the following structure:

 

typedef struct {
	int32_t dimSizes[2];
	double elt[1];
} DoubleArrayBase;
typedef DoubleArrayBase **DoubleArray;

void __stdcall SimpleDoubleArray(int32_t Channels, int32_t Points, 
	DoubleArray *DoubleArray);

In Delphi have defined the structure as follows:

type
  PDoubleArray = ^DoubleArray;
  DoubleArray = ^PDoubleArrayBase;
  PDoubleArrayBase = ^DoubleArrayBase;
  DoubleArrayBase = packed record
    dimSizes: array[0..1] of Int32;
    elt: array[0..0] of Double;
  end;

var
  procedure SimpleDoubleArray(Channels, Points : Int32; TestDoubleArray: PDoubleArray);stdcall; external DLLDirectory;

and call the function :

procedure TForm8.btn1Click(Sender: TObject);
var
  TestDoubleArray : DoubleArray;

begin
  SimpleDoubleArray(5,5,@Testdoublearray);
end;

 

My question is that when i assign the DoubleArray as the output of a function, how do i read the information that is stored in the TestDoubleArray?  In other words, how do i access the DoubleArrayBase record values of dimSizes and elt from the TestDoubleArray variable that i passed to the function? I am basically translating what is done in this post: https://lavag.org/topic/20486-lv-dll-creates-mysterious-doublearray-class/ to a Delphi equivalent. 

Edited August 11, 2022 by Snieres

[David Heffernan 2293]

We don't know what PDoubleArray1 is because the definition isn't here.  However, you pass @Testdoublearray which is a pointer to pointer to record.  But the native code expects pointer to struct.  Clearly a mismatch.  Given the various edits that have gone on between the real code and the code you posted, this could be wrong.

Edited August 11, 2022 by David Heffernan

[Snieres 0]

@David Heffernan That was a typo, it is PDoubleArray. Original Post has been edited.

Edited August 11, 2022 by Snieres

[Remy Lebeau 1257]

2 hours ago, Snieres said:

I have a type LabView created DLL that creates the following structure:

<sigh> And here we go again...

 

This is a followup to these StackOverflow questions:

 

https://stackoverflow.com/questions/73313071/

https://stackoverflow.com/questions/73254575/

Edited August 11, 2022 by Remy Lebeau

[Snieres 0]

Yes Remy, it is. I have updated the question on stack. What you have is correct, but how do i go about viewing the data stored in the doublearray? It is more of a carry on question. I can not figure out how to get to the dimsizes and the elt through the DoubleArray. I have broken this question down to a basic 2d array.

Edited August 11, 2022 by Snieres

[Remy Lebeau 1257]

13 minutes ago, Snieres said:

Yes Remy, it is. I have updated the question on stack. What you have is correct, but how do i go about viewing the data stored in the doublearray?

I just answered that on StackOverflow, go see my update.

[David Heffernan 2293]

Looking at the update are you sure the function takes pointer to pointer to pointer to struct? 

[Snieres 0]

16 minutes ago, David Heffernan said:

Looking at the update are you sure the function takes pointer to pointer to pointer to struct? 

@David Heffernan Yes