Can i pass array with jna to .net?

[K-Full]

I am sorry about all the questions. I do not know well if you search on Google, so please let me know.
Can I pass an array from JNA to .net using UnmanagedExports?

Here is my code

//java
int arr = new int[2];
arr[0] = 1;
arr[1] = 2;
test(arr);

//JNA
public interface VbWrapper extends Library {
public int test(int[] intArr);
}

//.net
<DllExport("test", CallingConvention.StdCall)>
Function test(ByVal arr() As Integer) As Integer
MsgBox(arr.length) ' printed 1
MsgBox(arr(1)) ' invalid memory access 

Am I making a mistake?

[3F]

well, all your questions is more related for C/C++ instead of Java, I mean just read more about PInvoke mechanism ! Java (JNA impl.) plays by the same rules.

ok, try this:

Java

public interface CAPI extends Library
{
    public void setArray(int[] data);
}
...   
CAPI lib = Native.loadLibrary(...);
...
int[] data = new int[]{ 0x20, 0x40, -0x3F, 0xFF };
...
lib.setArray(data);

.NET (C#)

[DllExport]
public static void setArray(IntPtr ptr)
{
    int[] data = new int[4];
    Marshal.Copy(ptr, data, 0, data.Length);
}

C/C++

and other: you can read it manually or with similar scheme, that is:

0x00000225C935A880: 20 00 00 00 40 00 00 00 c1 ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 18 40 9b de fa 7f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .........
//                  \---------/ \---------/ \---------/ \---------/ - *a little-endian (LE) byte order for my pc + the size of int type for this case is 4

...

Marshal.ReadInt32(ptr); // 0x20
Marshal.ReadInt32(ptr, Marshal.SizeOf(typeof(Int32))); // 0x40
...

thus we can also something like this:

[DllExport]
public static void setArray(IntPtr ptr)
{
    Func<IntPtr, int, int[]> _ = delegate(IntPtr _ptr, int size)
    {
        int[] ret = new int[size];
        int ofs = Marshal.SizeOf(typeof(Int32));

        for(int i = 0; i < size; ++i) {
            ret[i] = Marshal.ReadInt32(ptr, ofs * i);
        }

        return ret;
    };
    
    int[] data = _(ptr, 4); // 0x20, 0x40, -0x3F, 0xFF
}

use Conari for raw access like above.

etc.

I do not know well if you search on Google, so please let me know

amm, what o_O

[K-Full]

Thank you for your answer.
I solved it.

//java
  String intArrStr = "1 2";
  test(intArrStr );

//JNA
public interface VbLib extends Library {
  public int test(String intArrStr);
}

//.net
<DllExport("test", CallingConvention.StdCall)>
Function test(ByVal intArrStr As String) As Integer
  Dim arrStr As String() = intArrStr.Split(" ")
  Dim intArr(2) As Integer
  intArr(0) = Int32.Parse(arrStr(0))
  intArr(1) = Int32.Parse(arrStr(1))
End Function

This is not cool solution.
jna can't mapping two-dimension array.
But this code can solve it.

Many thanks for your help.

[3F]

why you don't want to use a pointer to access to your data in memory ?

This is not cool solution.

this is omg solution :)

jna can't mapping two-dimension array.

the map should be same, but seems yes, jna does not support multidimensional arrays. Try report to JNA dev for support this:

new int[][]{ {0x20, 0x40}, {-0x3F, 0xFF} } //  java.lang.IllegalArgumentException: Unsupported array argument type: class [I

the logic should be same, for example

Native C++ (unmanaged):

HMODULE lib     = LoadLibrary(_T("..."));
FARPROC pvar    = GetProcAddress(lib, "setArray");

typedef void(*pfunc)(int**);

auto data = new int[2][2]{ { 0x20, 0x40 },{ -0x3F, 0xFF } };

((pfunc)pvar)((int**)data);

0x00000223C1496450  20 00 00 00 40 00 00 00 c1 ff ff ff ff 00 00 00 fd fd fd fd 00 00 00 00 f5 3d 23 88 00 12 00 88 10 00 00 00 00 ...

C#:

new int[,] { { 0x20, 0x40 }, { -0x3F, 0xFF } };

0x000001B44E669150  20 00 00 00 40 00 00 00 c1 ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 18 40 9b de fa 7f 00 00 00 00 00 00 00 ...

But anyway you can map your data by similar scheme and consider it as you need later. Please do not torture the String for this :)