Hi, I've got a dll (device.dll) file that I want to use in my java application. I can't change the dll file I only have a api for it.

Methods in the dll: int open(int typ, WINCALLBACKBCOM cbf, void* param=NULL) int close() int getInfo(int typ, int* len, char *info)

The method getInfo should return the length of buffers in the len parameter and the pointer of buffers should be in info. I use IntByReference for len and a String for info, but when I print them after the method getInfo the data is still the same. Why haven't they been updated? Am I doing something wrong here? Hope someone can help me and that I'm posting in the right mailing list.

My java classes:

/--------CLibrary.java------------\ import com.sun.jna.*; public interface CLibrary extends Library {

interface WINCALLBACKBCOM extends Callback { public int callback(int nStatus, int nTracks); }

}

/--------Device.java--------------\ import com.sun.jna.*; import com.sun.jna.ptr.* ;

public interface Device extends Library {

int open(int typ, CLibrary.WINCALLBACKBCOM cb, Pointer param); int closeReadDevice(); int getInfo(int typ, IntByReference len, String info);

Device instance = (Device) Native.loadLibrary("Device", Device.class); }

/--------test.java------------------\ import com.sun.jna.*; import com.sun.jna.ptr.*;

public class test { public test() { }

public static void main(String[] args) { try { Device lib = Device.instance;

if (lib != null) { System.out.println("loaded);

System.out.println("open"); String[] s = {""}; Pointer p = new StringArray(s); int e = lib.open(0, new CLibrary.WINCALLBACKBCOM() { public int callback(int nStatus, int nTracks) { System.out.println("callback: nStatus = " + nStatus + " nTracks = " + nTracks); return 0; } }, p); System.out.println("open error: " + Integer.toHexString(e));

Thread.sleep(2500);

System.out.println("getInfo"); String s3 = ""; IntByReference iref = new IntByReference(1); int e2 = lib.getInfo(0, iref, s3); System.out.println("getInfo error: " + Integer.toHexString (e2)); System.out.println ("S3 = " + s3); System.out.println("Iref = " + iref.getValue()); } else { System.out.println("Load failed"); } } catch (Exception e) { System.out.println("Exception: " + e.getMessage()); e.printStackTrace(); } }

/--------Result---------------------\ loaded open open error: 0 getInfo getInfo error: 0 S3 = Iref = 1