static extern uint GetFontUnicodeRanges(IntPtr hdc, IntPtr lpgs);

    public static extern uint GetFontUnicodeRanges(IntPtr hdc, IntPtr lpgs);

    public List<FontRange> GetFontUnicodeRanges(Font font)

        uint size = GetFontUnicodeRanges(hdc, IntPtr.Zero);

        GetFontUnicodeRanges(hdc, glyphSet);

// List<FontRange> fontRanges = GetFontUnicodeRanges(this.Font);

For more on uncode blocks see: http://pinvoke.net/default.aspx/gdi32/GetFontUnicodeRanges.html