I tried to change as you suggested. I still get the same error :

Exception c0000005, at 77DE1C38

Access violation: attempting to write memory at address 00000000

Code now looks like this:

package jniwrapper;

import com.jniwrapper.DefaultLibraryLoader;

import com.jniwrapper.Function;

import com.jniwrapper.Library;

import com.jniwrapper.Parameter;

import com.jniwrapper.Pointer;

import com.jniwrapper.Structure;

import com.jniwrapper.UInt32;

import com.jniwrapper.ULongInt;

import com.jniwrapper.UShortInt;

import com.jniwrapper.WideString;

/**

*

*/

/**

• @author Anders Nilsson

*

*/

public class TestLsaOpenPolicy {

    private static class LSA_OBJECT_ATTRIBUTES extends Structure {

/*

typedef struct LSAOBJECT_ATTRIBUTES {

     ULONG Length;

     HANDLE RootDirectory;

     PLSA_UNICODE_STRING ObjectName;

     ULONG Attributes;

     PVOID SecurityDescriptor;

     PVOID SecurityQualityOfService;

} LSA_OBJECT_ATTRIBUTES,  *PLSA_OBJECT_ATTRIBUTES;

*/         

        public ULongInt length = new ULongInt();

        public Pointer.Void rootDirectory = new Pointer.Void();

        public WideString objectName = new WideString();

        public ULongInt attributes = new ULongInt();

        public Pointer.Void securityDescriptor = new Pointer.Void();

        public Pointer.Void securityQualityOfService = new Pointer.Void();

        public LSA_OBJECT_ATTRIBUTES()

        {

            init(new Parameter[] {

                      length,

                      rootDirectory,

                      objectName,

                      attributes,

                      securityDescriptor,

                      securityQualityOfService

            });

        }

    }

    private static class LSA_UNICODE_STRING  extends Structure {

    /*

typedef struct LSAUNICODE_STRING {

     USHORT Length;

     USHORT MaximumLength;

     PWSTR Buffer;

} LSA_UNICODE_STRING,  *PLSA_UNICODE_STRING;

     */

         public UShortInt length  = new UShortInt();

         public UShortInt maximumLength  = new UShortInt();

         public WideString buffer = new WideString();

         public LSA_UNICODE_STRING() {

              init(new Parameter[] {length, maximumLength, new Pointer(buffer)});

         }

    }

     private Library _advapi;

     private Library _kernel;

     public TestLsaOpenPolicy() {

          _kernel = new Library("kernel32");          

          _advapi = new Library("Advapi32");

     }

     /**

• @param args

      */

     public static void main(String[] args) {

          TestLsaOpenPolicy t;

          t = new TestLsaOpenPolicy();

          t.execute(args);

     }

     protected void execute(String[] args) {

          Parameter[] argn;

          Pointer.Void rtrn;

          DefaultLibraryLoader.getInstance().addPath(

          "G:
eclipse
newton
MetaData
OSAccessWinJNIWrapper
extlib");

          // Open Policy

          Function openPolicy = _advapi.getFunction("LsaOpenPolicy");

          LSA_UNICODE_STRING systemName;

          UInt32 lsaHandle;

          systemName = new LSA_UNICODE_STRING();

          systemName.length.setValue(0);

          systemName.maximumLength.setValue(30);

          systemName.buffer.setValue("");

          lsaHandle = new UInt32(0);

          rtrn = new Pointer.Void(0);

          argn = new Parameter[4];

          argn[0] = new Pointer(systemName);

          argn[1] = new LSA_OBJECT_ATTRIBUTES();

          argn[2] = new UInt32(0x0000FFFF);

          argn[3] = new Pointer(lsaHandle);

          openPolicy.invoke(rtrn, argn);

          System.out.println(rtrn);

     }

     private long getLastError(boolean clear)

    {

        UInt32 r = new UInt32();

        Function getLE = _kernel.getFunction("GetLastError");

        getLE.invoke(r);

        long errCode = r.getValue();

        if (clear)

        {

            UInt32 zero = new UInt32(0);

            Function setLE = _kernel.getFunction("SetLastError");

            setLE.invoke(null, zero);

        }

        return errCode;

    }     

}

Also, the parameter you suggested I change is in so the function I call shouldn't write to it anyway.

Regards

Anders

Thanks a lot. Works great now.

Regards

Anders