+@cindex file-name encoding, MS-Windows
+@vindex w32-unicode-filenames
+ When Emacs runs on MS-Windows versions that are descendants of the
+NT family (Windows 2000, XP, Vista, Windows 7, and Windows 8), the
+value of @code{file-name-coding-system} is largely ignored, as Emacs
+by default uses APIs that allow to pass Unicode file names directly.
+By contrast, on Windows 9X, file names are encoded using
+@code{file-name-coding-system}, which should be set to the codepage
+(@pxref{Coding Systems, codepage}) pertinent for the current system
+locale. The value of the variable @code{w32-unicode-filenames}
+controls whether Emacs uses the Unicode APIs when it calls OS
+functions that accept file names. This variable is set by the startup
+code to @code{nil} on Windows 9X, and to @code{t} on newer versions of
+MS-Windows.
+