Calling the Unicode Version of a DLL Function

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Suppose that instead of calling the ANSI version of the MessageBox function, you want to call the Unicode version. You can do this by using the unicode modifier with the @dll.import directive:

/** @dll.import("USER32",unicode) */
  static native int MessageBox(int hwnd, String text, String title,
                               int style);

Since the unicode modifier is present, the Microsoft VM will go through the following steps:

  1. The strings "text" and "title" are converted to Unicode null-terminated strings.

  2. The VM attempts to find an export named MessageBox in USER32.DLL.

  3. This attempt fails. The VM appends a "W" onto the name and looks for an export named MessageBoxW.

  4. This attempt succeeds, and the VM invokes the MessageBoxW function.