Hi all,

i have taken an example found in the mailing-list archive for a callback for a keyboard event. The example doesn't worked, so I have completed it and now works a little better, but as soon as the callback procedure is called the JVM crashes.

public class Keyboard {

Pointer hinst; KeyboardProc kbListener; Pointer handle;

public Keyboard() { hinst = Kernel32.INSTANCE.GetModuleHandleW(null);

kbListener = new KeyboardProc() { public int callback(int code, WPARAM wParam, LPARAM lParam) { System.out.println("keyboard callback code: " +code + " wParam "+ wParam + " lParam "+lParam );

return User32.INSTANCE.CallNextHookEx(handle, code, wParam, lParam); } }; handle = User32.INSTANCE.SetWindowsHookExW (User32.WH_KEYBOARD_LL, kbListener, hinst, 0); }

protected void finalize() throws Throwable { User32.INSTANCE.UnhookWindowsHookExW(handle); super.finalize(); }

public static void main(String[] args) { System.out.println("Start."); Keyboard instance = new Keyboard(); BufferedReader br = new BufferedReader( new InputStreamReader( System.in ) ); try { boolean go = true; while(go){ MSG msg = new MSG(); go = User32.INSTANCE.GetMessageW (msg,null,0,0); //fUser32.INSTANCE.DispatchMessageW(msg);

} br.readLine(); } catch( IOException ex ) {} System.out.println("Done."); }

public interface KeyboardProc extends StdCallCallback { int callback(int code, WPARAM wParam, LPARAM lParam); } }

// LPARAM and WAPRAM def:

public static class LPARAM extends LONG_PTR { public LPARAM() { this(0); } public LPARAM(long value) { super(value); } } public static class WPARAM extends IntegerType { public WPARAM() { this(0); } public WPARAM(long value) { super(Pointer.SIZE, value); } }

The function callback is called only one, then the JVM crashes. note that if I call SetWindowsHookExW with WH_KEYBOARD no callback function is called.

The crash is maybe caused by a incorrect type conversion?