From: mark...@metoffice.gov.uk [mailto:mark...@metoffice.gov.uk] Sent: Friday, February 29, 2008 6:09 PM To: feed...@java-net.dev.java.net Subject: RE: https://jna.dev.java.net/#demos

It may be I need to show you where the issue is, so here's the simplest example from your docs:

4. Declare a Java interface to hold the native library methods by extending the Library interface. Following is an example of mapping for the Windows kernel32 library.

package com.sun.jna.examples.win32;

import com.sun.jna.*;

// kernel32.dll uses the __stdcall calling convention (check the function // declaration for "WINAPI"), so extend StdCallLibrary // Most C libraries will just extend com.sun.jna.Library, public interface Kernel32 extends StdCallLibrary { // Method declarations, constant and structure definitions go here }

5. In your interface, allocate an instance of the native library using the Native.loadLibrary(Class) method, providing the native library interface you defined in step (4).

Kernel32 INSTANCE = (Kernel32) Native.loadLibrary("kernel32", Kernel32.class);

[OK, so where does it go? there's no other declaration of what class/interface/doodad but it doesn't go inside the declaration of #4.]

6. Declare methods that mirror the functions in the target library by defining Java methods with the same name and argument types as the native function

public static class SYSTEMTIME extends Structure { public short wYear; public short wMonth; public short wDayOfWeek; public short wDay; public short wHour; public short wMinute; public short wSecond; public short wMilliseconds; }

[and where does this go? Nothing said. New class? New interface? Same as #5 (compounding the questions for #5...)]

7. You can now invoke methods on the library instance just like any other Java class. For a more extensive example, see the WindowUtils and ShapedWindowDemo classes.

[Yeah, but the class I did look at (FileMonitor, 'cos I'm on linux), it doesn't call Native.loadLibrary. So that doesn't answer my queries above]

See how if you don't already know how to do this, you aren't any better off after reading this "howto".

On Fri, 2008-02-29 at 12:28 +0000, Mark Hackett wrote: