Question

Let us consider that we need to pass a structured form of callbacks to native code dll.
One of the callbacks has the following form in C notation:

int myfunc (int arg1,int* arg2,int arg3,int arg4);//it is marked as stdcall in real app

Here arg2 is an array of ints. arg1 determines the number of elements in arg2.

Here is Java code:

 public class TRCallbackCollection extends Structure{
       public int fieldsCount;    
       public StdCallLibrary.StdCallCallback myfunc;
//...
    }
//...
TRCallbackCollection callbacks= new   TRCallbackCollection();
callbacks.fieldsCount = 7;       
callbacks.myfunc = new StdCallLibrary.StdCallCallback(){
 public int callback (int arg1, int[] arg2,int arg3,int arg4) {            
  return 0;
 }
};

I’ve got the followin error:

java.lang.IllegalArgumentException: Structure field “myfunc” was
declared as interface
com.sun.jna.win32.StdCallLibrary$StdCallCallback, which is not
supported within a Structure,

when I try to init native dll with the instance of TRCallbackCollection structure:

lib.InitKernel(callbacks,5);

Other callbacks work fine. I think that the problem is linked with int[] arg2 in method. How should I transform it and use as the array within callback?

Answer 1

Success; other StdCallCallback fields worked!

Fortunately, I’ve solved the problem. I used Pointer arg2 instead of int[] arg2.