title: JNA access to 64-bit DLL (Windows7 64-bit)
body: <p>Could you please advice. I have simple DLL (under Windows 7 64-bit) and simple Java code with JNA access to this DLL.
  The problem is when I use 64-bit version of this DLL looks like I can't get parameter from Java in my DLL test function <strong>giveIntGetInt</strong>, and I have no problem when I use 32-bit DLL.
  Where I was wrong?
  Thank you!</p>
  
  <pre><code>import com.sun.jna.Library;
  import com.sun.jna.Native;
  import com.sun.jna.Platform;
  import com.sun.jna.Pointer;
  
  /** Simple example of native library declaration and usage. */
  public class HelloWorld {
      public interface simpleDLL extends Library {
          simpleDLL INSTANCE = (simpleDLL) Native.loadLibrary(
              (Platform.isWindows() ? "simpleDLL" : "simpleDLLLinuxPort"), simpleDLL.class);
           int giveIntGetInt(int a);               // int giveIntGetInt(int a);
      }
  
      public static void main(String[] args) {
       int b = simpleDLL.INSTANCE.giveIntGetInt(2);
       System.out.println("Hello, World\n");
  
       System.out.println(String.format("Argument %d", b));
  
      }
  }
  </code></pre>
  
  <p>this is C dll method:</p>
  
  <pre><code>int simpleDLL::giveIntGetInt(int a)
      {
          return 2*a;
      }
  </code></pre>
  
  <p>For example, this is I've got with 64-bit dll:</p>
  
  <pre><code>Hello, World 
  Argument 181140
  </code></pre>
  
  <p>32-bit dll:</p>
  
  <pre><code>Hello, World 
  Argument 4
  </code></pre>