* Picture Mode:: Editing pictures made up of characters
using the quarter-plane screen model.
* Fortran:: Fortran mode and its special features.
+* MS-DOG::
* Index::
@end menu
Type @samp{;?} or @samp{;C-h} to display a list of all the built-in
Fortran abbrevs and what they stand for.
+
+@node MS-DOG
+@chapter Emacs and MS-DOS
+@cindex MS-DOG
+@cindex MS-DOS peculiarities
+
+ This section briefly describes the peculiarities of using Emacs on
+the MS-DOS ``operating system'' (also known as ``MS-DOG'').
+Information about Emacs and Microsoft's current operating system
+Windows (also known as ``Losedows) is in the main Emacs manual
+(@pxref{Emacs and Microsoft Systems,,, emacs, the Emacs Manual}).
+
+ If you build Emacs for MS-DOS, the binary will also run on Windows
+3.X, Windows NT, Windows 9X/ME, Windows 2000, or OS/2 as a DOS
+application; all of this chapter applies for all of those systems, if
+you use an Emacs that was built for MS-DOS.
+
+ @xref{Text and Binary,,,emacs, the Emacs Manual}, for information
+about Emacs' special handling of text files under MS-DOS (and
+Windows).
+
+@menu
+* Keyboard: MS-DOS Keyboard. Keyboard conventions on MS-DOS.
+* Mouse: MS-DOS Mouse. Mouse conventions on MS-DOS.
+* Display: MS-DOS Display. Fonts, frames and display size on MS-DOS.
+* Files: MS-DOS File Names. File name conventions on MS-DOS.
+* Printing: MS-DOS Printing. How to specify the printer on MS-DOS.
+* I18N: MS-DOS and MULE. Support for internationalization on MS-DOS.
+* Processes: MS-DOS Processes. Running subprocesses on MS-DOS.
+@end menu
+
+@node MS-DOS Keyboard
+@section Keyboard Usage on MS-DOS
+
+@kindex DEL @r{(MS-DOS)}
+@kindex BS @r{(MS-DOS)}
+ The key that is called @key{DEL} in Emacs (because that's how it is
+designated on most workstations) is known as @key{BS} (backspace) on a
+PC. That is why the PC-specific terminal initialization remaps the
+@key{BS} key to act as @key{DEL}; the @key{DELETE} key is remapped to act
+as @kbd{C-d} for the same reasons.
+
+@kindex C-g @r{(MS-DOS)}
+@kindex C-BREAK @r{(MS-DOS)}
+@cindex quitting on MS-DOS
+ Emacs built for MS-DOS recognizes @kbd{C-@key{BREAK}} as a quit
+character, just like @kbd{C-g}. This is because Emacs cannot detect
+that you have typed @kbd{C-g} until it is ready for more input. As a
+consequence, you cannot use @kbd{C-g} to stop a running command
+(@pxref{Quitting,,,emacs, the Emacs Manual}). By contrast,
+@kbd{C-@key{BREAK}} @emph{is} detected as soon as you type it (as
+@kbd{C-g} is on other systems), so it can be used to stop a running
+command and for emergency escape (@pxref{Emergency Escape,,,emacs, the
+Emacs Manual}).
+
+@cindex Meta (under MS-DOS)
+@cindex Hyper (under MS-DOS)
+@cindex Super (under MS-DOS)
+@vindex dos-super-key
+@vindex dos-hyper-key
+ The PC keyboard maps use the left @key{ALT} key as the @key{META} key.
+You have two choices for emulating the @key{SUPER} and @key{HYPER} keys:
+choose either the right @key{CTRL} key or the right @key{ALT} key by
+setting the variables @code{dos-hyper-key} and @code{dos-super-key} to 1
+or 2 respectively. If neither @code{dos-super-key} nor
+@code{dos-hyper-key} is 1, then by default the right @key{ALT} key is
+also mapped to the @key{META} key. However, if the MS-DOS international
+keyboard support program @file{KEYB.COM} is installed, Emacs will
+@emph{not} map the right @key{ALT} to @key{META}, since it is used for
+accessing characters like @kbd{~} and @kbd{@@} on non-US keyboard
+layouts; in this case, you may only use the left @key{ALT} as @key{META}
+key.
+
+@kindex C-j @r{(MS-DOS)}
+@vindex dos-keypad-mode
+ The variable @code{dos-keypad-mode} is a flag variable that controls
+what key codes are returned by keys in the numeric keypad. You can also
+define the keypad @key{ENTER} key to act like @kbd{C-j}, by putting the
+following line into your @file{_emacs} file:
+
+@smallexample
+;; @r{Make the @key{ENTER} key from the numeric keypad act as @kbd{C-j}.}
+(define-key function-key-map [kp-enter] [?\C-j])
+@end smallexample
+
+@node MS-DOS Mouse
+@section Mouse Usage on MS-DOS
+
+@cindex mouse support under MS-DOS
+ Emacs on MS-DOS supports a mouse (on the default terminal only).
+The mouse commands work as documented, including those that use menus
+and the menu bar (@pxref{Menu Bar,,,emacs, the Emacs Manual}). Scroll
+bars don't work in MS-DOS Emacs. PC mice usually have only two
+buttons; these act as @kbd{Mouse-1} and @kbd{Mouse-2}, but if you
+press both of them together, that has the effect of @kbd{Mouse-3}. If
+the mouse does have 3 buttons, Emacs detects that at startup, and all
+the 3 buttons function normally, as on X.
+
+ Help strings for menu-bar and pop-up menus are displayed in the echo
+area when the mouse pointer moves across the menu items. Highlighting
+of mouse-sensitive text (@pxref{Mouse References,,,emacs, the Emacs
+Manual}) is also supported.
+
+@cindex mouse, set number of buttons
+@findex msdos-set-mouse-buttons
+ Some versions of mouse drivers don't report the number of mouse
+buttons correctly. For example, mice with a wheel report that they
+have 3 buttons, but only 2 of them are passed to Emacs; the clicks on
+the wheel, which serves as the middle button, are not passed. In
+these cases, you can use the @kbd{M-x msdos-set-mouse-buttons} command
+to tell Emacs how many mouse buttons to expect. You could make such a
+setting permanent by adding this fragment to your @file{_emacs} init
+file:
+
+@example
+;; @r{Treat the mouse like a 2-button mouse.}
+(msdos-set-mouse-buttons 2)
+@end example
+
+@cindex Windows clipboard support
+ Emacs built for MS-DOS supports clipboard operations when it runs on
+Windows. Commands that put text on the kill ring, or yank text from
+the ring, check the Windows clipboard first, just as Emacs does on the
+X Window System (@pxref{Mouse Commands,,,emacs, the Emacs Manual}).
+Only the primary selection and the cut buffer are supported by MS-DOS
+Emacs on Windows; the secondary selection always appears as empty.
+
+ Due to the way clipboard access is implemented by Windows, the
+length of text you can put into the clipboard is limited by the amount
+of free DOS memory that is available to Emacs. Usually, up to 620KB of
+text can be put into the clipboard, but this limit depends on the system
+configuration and is lower if you run Emacs as a subprocess of
+another program. If the killed text does not fit, Emacs outputs a
+message saying so, and does not put the text into the clipboard.
+
+ Null characters also cannot be put into the Windows clipboard. If the
+killed text includes null characters, Emacs does not put such text into
+the clipboard, and displays in the echo area a message to that effect.
+
+@vindex dos-display-scancodes
+ The variable @code{dos-display-scancodes}, when non-@code{nil},
+directs Emacs to display the @acronym{ASCII} value and the keyboard scan code of
+each keystroke; this feature serves as a complement to the
+@code{view-lossage} command, for debugging.
+
+@node MS-DOS Display
+@section Display on MS-DOS
+@cindex faces under MS-DOS
+@cindex fonts, emulating under MS-DOS
+
+ Display on MS-DOS cannot use font variants, like bold or italic, but
+it does support multiple faces, each of which can specify a foreground
+and a background color. Therefore, you can get the full functionality
+of Emacs packages that use fonts (such as @code{font-lock}, Enriched
+Text mode, and others) by defining the relevant faces to use different
+colors. Use the @code{list-colors-display} command (@pxref{Frame
+Parameters,,,emacs, the Emacs Manual}) and the
+@code{list-faces-display} command (@pxref{Faces,,,emacs, the Emacs
+Manual}) to see what colors and faces are available and what they look
+like.
+
+ @xref{MS-DOS and MULE}, later in this chapter, for information on
+how Emacs displays glyphs and characters that aren't supported by the
+native font built into the DOS display.
+
+@cindex cursor shape on MS-DOS
+ When Emacs starts, it changes the cursor shape to a solid box. This
+is for compatibility with other systems, where the box cursor is the
+default in Emacs. This default shape can be changed to a bar by
+specifying the @code{cursor-type} parameter in the variable
+@code{default-frame-alist} (@pxref{Creating Frames,,,emacs, the Emacs
+Manual}). The MS-DOS terminal doesn't support a vertical-bar cursor,
+so the bar cursor is horizontal, and the @code{@var{width}} parameter,
+if specified by the frame parameters, actually determines its height.
+For this reason, the @code{bar} and @code{hbar} cursor types produce
+the same effect on MS-DOS. As an extension, the bar cursor
+specification can include the starting scan line of the cursor as well
+as its width, like this:
+
+@example
+ '(cursor-type bar @var{width} . @var{start})
+@end example
+
+@noindent
+In addition, if the @var{width} parameter is negative, the cursor bar
+begins at the top of the character cell.
+
+@cindex frames on MS-DOS
+ The MS-DOS terminal can only display a single frame at a time. The
+Emacs frame facilities work on MS-DOS much as they do on text-only
+terminals (@pxref{Frames,,,emacs, the Emacs Manual}). When you run
+Emacs from a DOS window on MS-Windows, you can make the visible frame
+smaller than the full screen, but Emacs still cannot display more than
+a single frame at a time.
+
+@cindex frame size under MS-DOS
+@findex mode4350
+@findex mode25
+ The @code{mode4350} command switches the display to 43 or 50
+lines, depending on your hardware; the @code{mode25} command switches
+to the default 80x25 screen size.
+
+ By default, Emacs only knows how to set screen sizes of 80 columns by
+25, 28, 35, 40, 43 or 50 rows. However, if your video adapter has
+special video modes that will switch the display to other sizes, you can
+have Emacs support those too. When you ask Emacs to switch the frame to
+@var{n} rows by @var{m} columns dimensions, it checks if there is a
+variable called @code{screen-dimensions-@var{n}x@var{m}}, and if so,
+uses its value (which must be an integer) as the video mode to switch
+to. (Emacs switches to that video mode by calling the BIOS @code{Set
+Video Mode} function with the value of
+@code{screen-dimensions-@var{n}x@var{m}} in the @code{AL} register.)
+For example, suppose your adapter will switch to 66x80 dimensions when
+put into video mode 85. Then you can make Emacs support this screen
+size by putting the following into your @file{_emacs} file:
+
+@example
+(setq screen-dimensions-66x80 85)
+@end example
+
+ Since Emacs on MS-DOS can only set the frame size to specific
+supported dimensions, it cannot honor every possible frame resizing
+request. When an unsupported size is requested, Emacs chooses the next
+larger supported size beyond the specified size. For example, if you
+ask for 36x80 frame, you will get 40x80 instead.
+
+ The variables @code{screen-dimensions-@var{n}x@var{m}} are used only
+when they exactly match the specified size; the search for the next
+larger supported size ignores them. In the above example, even if your
+VGA supports 38x80 dimensions and you define a variable
+@code{screen-dimensions-38x80} with a suitable value, you will still get
+40x80 screen when you ask for a 36x80 frame. If you want to get the
+38x80 size in this case, you can do it by setting the variable named
+@code{screen-dimensions-36x80} with the same video mode value as
+@code{screen-dimensions-38x80}.
+
+ Changing frame dimensions on MS-DOS has the effect of changing all the
+other frames to the new dimensions.
+
+@node MS-DOS File Names
+@section File Names on MS-DOS
+@cindex file names under MS-DOS
+@cindex init file, default name under MS-DOS
+
+ MS-DOS normally uses a backslash, @samp{\}, to separate name units
+within a file name, instead of the slash used on other systems. Emacs
+on MS-DOS permits use of either slash or backslash, and also knows
+about drive letters in file names.
+
+ On MS-DOS, file names are case-insensitive and limited to eight
+characters, plus optionally a period and three more characters. Emacs
+knows enough about these limitations to handle file names that were
+meant for other operating systems. For instance, leading dots
+@samp{.} in file names are invalid in MS-DOS, so Emacs transparently
+converts them to underscores @samp{_}; thus your default init file
+(@pxref{Init File,,,emacs, the Emacs Manual}) is called @file{_emacs}
+on MS-DOS. Excess characters before or after the period are generally
+ignored by MS-DOS itself; thus, if you visit the file
+@file{LongFileName.EvenLongerExtension}, you will silently get
+@file{longfile.eve}, but Emacs will still display the long file name
+on the mode line. Other than that, it's up to you to specify file
+names which are valid under MS-DOS; the transparent conversion as
+described above only works on file names built into Emacs.
+
+@cindex backup file names on MS-DOS
+ The above restrictions on the file names on MS-DOS make it almost
+impossible to construct the name of a backup file (@pxref{Backup
+Names,,,emacs, the Emacs Manual}) without losing some of the original
+file name characters. For example, the name of a backup file for
+@file{docs.txt} is @file{docs.tx~} even if single backup is used.
+
+@cindex file names under Windows 95/NT
+@cindex long file names in DOS box under Windows 95/NT
+ If you run Emacs as a DOS application under Windows 9X, Windows ME, or
+Windows 2000, you can turn on support for long file names. If you do
+that, Emacs doesn't truncate file names or convert them to lower case;
+instead, it uses the file names that you specify, verbatim. To enable
+long file name support, set the environment variable @env{LFN} to
+@samp{y} before starting Emacs. Unfortunately, Windows NT doesn't allow
+DOS programs to access long file names, so Emacs built for MS-DOS will
+only see their short 8+3 aliases.
+
+@cindex @env{HOME} directory under MS-DOS
+ MS-DOS has no notion of home directory, so Emacs on MS-DOS pretends
+that the directory where it is installed is the value of the @env{HOME}
+environment variable. That is, if your Emacs binary,
+@file{emacs.exe}, is in the directory @file{c:/utils/emacs/bin}, then
+Emacs acts as if @env{HOME} were set to @samp{c:/utils/emacs}. In
+particular, that is where Emacs looks for the init file @file{_emacs}.
+With this in mind, you can use @samp{~} in file names as an alias for
+the home directory, as you would on GNU or Unix. You can also set
+@env{HOME} variable in the environment before starting Emacs; its
+value will then override the above default behavior.
+
+ Emacs on MS-DOS handles the directory name @file{/dev} specially,
+because of a feature in the emulator libraries of DJGPP that pretends
+I/O devices have names in that directory. We recommend that you avoid
+using an actual directory named @file{/dev} on any disk.
+
+@node MS-DOS Printing
+@section Printing and MS-DOS
+
+ Printing commands, such as @code{lpr-buffer}
+(@pxref{Printing,,,emacs, the Emacs Manual }) and
+@code{ps-print-buffer} (@pxref{PostScript,,,emacs, the Emacs Manual})
+can work in MS-DOS and MS-Windows by sending the output to one of the
+printer ports, if a Posix-style @code{lpr} program is unavailable.
+The same Emacs variables control printing on all systems, but in some
+cases they have different default values on MS-DOS and MS-Windows.
+
+@vindex printer-name @r{(MS-DOS)}
+ If you want to use your local printer, printing on it in the usual DOS
+manner, then set the Lisp variable @code{lpr-command} to @code{""} (its
+default value) and @code{printer-name} to the name of the printer
+port---for example, @code{"PRN"}, the usual local printer port (that's
+the default), or @code{"LPT2"}, or @code{"COM1"} for a serial printer.
+You can also set @code{printer-name} to a file name, in which case
+``printed'' output is actually appended to that file. If you set
+@code{printer-name} to @code{"NUL"}, printed output is silently
+discarded (sent to the system null device).
+
+ On MS-Windows, when the Windows network software is installed, you can
+also use a printer shared by another machine by setting
+@code{printer-name} to the UNC share name for that printer---for example,
+@code{"//joes_pc/hp4si"}. (It doesn't matter whether you use forward
+slashes or backslashes here.) To find out the names of shared printers,
+run the command @samp{net view} at a DOS command prompt to obtain a list
+of servers, and @samp{net view @var{server-name}} to see the names of printers
+(and directories) shared by that server. Alternatively, click the
+@samp{Network Neighborhood} icon on your desktop, and look for machines
+which share their printers via the network.
+
+@cindex @samp{net use}, and printing on MS-Windows
+@cindex networked printers (MS-Windows)
+ If the printer doesn't appear in the output of @samp{net view}, or
+if setting @code{printer-name} to the UNC share name doesn't produce a
+hardcopy on that printer, you can use the @samp{net use} command to
+connect a local print port such as @code{"LPT2"} to the networked
+printer. For example, typing @kbd{net use LPT2:
+\\joes_pc\hp4si}@footnote{
+Note that the @samp{net use} command requires the UNC share name to be
+typed with the Windows-style backslashes, while the value of
+@code{printer-name} can be set with either forward- or backslashes.}
+causes Windows to @dfn{capture} the LPT2 port and redirect the printed
+material to the printer connected to the machine @code{joes_pc}.
+After this command, setting @code{printer-name} to @code{"LPT2"}
+should produce the hardcopy on the networked printer.
+
+ With some varieties of Windows network software, you can instruct
+Windows to capture a specific printer port such as @code{"LPT2"}, and
+redirect it to a networked printer via the @w{@code{Control
+Panel->Printers}} applet instead of @samp{net use}.
+
+ Some printers expect DOS codepage encoding of non-@acronym{ASCII} text, even
+though they are connected to a Windows machine which uses a different
+encoding for the same locale. For example, in the Latin-1 locale, DOS
+uses codepage 850 whereas Windows uses codepage 1252. @xref{MS-DOS and
+MULE}. When you print to such printers from Windows, you can use the
+@kbd{C-x RET c} (@code{universal-coding-system-argument}) command before
+@kbd{M-x lpr-buffer}; Emacs will then convert the text to the DOS
+codepage that you specify. For example, @kbd{C-x RET c cp850-dos RET
+M-x lpr-region RET} will print the region while converting it to the
+codepage 850 encoding. You may need to create the @code{cp@var{nnn}}
+coding system with @kbd{M-x codepage-setup}.
+
+ If you set @code{printer-name} to a file name, it's best to use an
+absolute file name. Emacs changes the working directory according to
+the default directory of the current buffer, so if the file name in
+@code{printer-name} is relative, you will end up with several such
+files, each one in the directory of the buffer from which the printing
+was done.
+
+@findex print-buffer @r{(MS-DOS)}
+@findex print-region @r{(MS-DOS)}
+@vindex lpr-headers-switches @r{(MS-DOS)}
+ The commands @code{print-buffer} and @code{print-region} call the
+@code{pr} program, or use special switches to the @code{lpr} program, to
+produce headers on each printed page. MS-DOS and MS-Windows don't
+normally have these programs, so by default, the variable
+@code{lpr-headers-switches} is set so that the requests to print page
+headers are silently ignored. Thus, @code{print-buffer} and
+@code{print-region} produce the same output as @code{lpr-buffer} and
+@code{lpr-region}, respectively. If you do have a suitable @code{pr}
+program (for example, from GNU Textutils), set
+@code{lpr-headers-switches} to @code{nil}; Emacs will then call
+@code{pr} to produce the page headers, and print the resulting output as
+specified by @code{printer-name}.
+
+@vindex print-region-function @r{(MS-DOS)}
+@cindex lpr usage under MS-DOS
+@vindex lpr-command @r{(MS-DOS)}
+@vindex lpr-switches @r{(MS-DOS)}
+ Finally, if you do have an @code{lpr} work-alike, you can set the
+variable @code{lpr-command} to @code{"lpr"}. Then Emacs will use
+@code{lpr} for printing, as on other systems. (If the name of the
+program isn't @code{lpr}, set @code{lpr-command} to specify where to
+find it.) The variable @code{lpr-switches} has its standard meaning
+when @code{lpr-command} is not @code{""}. If the variable
+@code{printer-name} has a string value, it is used as the value for the
+@code{-P} option to @code{lpr}, as on Unix.
+
+@findex ps-print-buffer @r{(MS-DOS)}
+@findex ps-spool-buffer @r{(MS-DOS)}
+@vindex ps-printer-name @r{(MS-DOS)}
+@vindex ps-lpr-command @r{(MS-DOS)}
+@vindex ps-lpr-switches @r{(MS-DOS)}
+ A parallel set of variables, @code{ps-lpr-command},
+@code{ps-lpr-switches}, and @code{ps-printer-name} (@pxref{PostScript
+Variables,,,emacs, the Emacs Manual}), defines how PostScript files
+should be printed. These variables are used in the same way as the
+corresponding variables described above for non-PostScript printing.
+Thus, the value of @code{ps-printer-name} is used as the name of the
+device (or file) to which PostScript output is sent, just as
+@code{printer-name} is used for non-PostScript printing. (There are
+two distinct sets of variables in case you have two printers attached
+to two different ports, and only one of them is a PostScript printer.)
+
+ The default value of the variable @code{ps-lpr-command} is @code{""},
+which causes PostScript output to be sent to the printer port specified
+by @code{ps-printer-name}, but @code{ps-lpr-command} can also be set to
+the name of a program which will accept PostScript files. Thus, if you
+have a non-PostScript printer, you can set this variable to the name of
+a PostScript interpreter program (such as Ghostscript). Any switches
+that need to be passed to the interpreter program are specified using
+@code{ps-lpr-switches}. (If the value of @code{ps-printer-name} is a
+string, it will be added to the list of switches as the value for the
+@code{-P} option. This is probably only useful if you are using
+@code{lpr}, so when using an interpreter typically you would set
+@code{ps-printer-name} to something other than a string so it is
+ignored.)
+
+ For example, to use Ghostscript for printing on an Epson printer
+connected to the @samp{LPT2} port, put this in your @file{_emacs} file:
+
+@example
+(setq ps-printer-name t) ; Ghostscript doesn't understand -P
+(setq ps-lpr-command "c:/gs/gs386")
+(setq ps-lpr-switches '("-q" "-dNOPAUSE"
+ "-sDEVICE=epson"
+ "-r240x72"
+ "-sOutputFile=LPT2"
+ "-Ic:/gs"))
+@end example
+
+@noindent
+(This assumes that Ghostscript is installed in the @file{"c:/gs"}
+directory.)
+
+@vindex dos-printer
+@vindex dos-ps-printer
+ For backwards compatibility, the value of @code{dos-printer}
+(@code{dos-ps-printer}), if it has a value, overrides the value of
+@code{printer-name} (@code{ps-printer-name}), on MS-DOS and MS-Windows
+only.
+
+
+@node MS-DOS and MULE
+@section International Support on MS-DOS
+@cindex international support @r{(MS-DOS)}
+
+ Emacs on MS-DOS supports the same international character sets as it
+does on GNU, Unix and other platforms (@pxref{International,,,emacs,
+the Emacs Manual}), including coding systems for converting between
+the different character sets. However, due to incompatibilities
+between MS-DOS/MS-Windows and other systems, there are several
+DOS-specific aspects of this support that you should be aware of.
+This section describes these aspects.
+
+ The description below is largely specific to the MS-DOS port of
+Emacs, especially where it talks about practical implications for
+Emacs users. For other operating systems, see the @file{code-pages.el}
+package, which implements support for MS-DOS- and MS-Windows-specific
+encodings for all platforms other than MS-DOS.
+
+@table @kbd
+@item M-x dos-codepage-setup
+Set up Emacs display and coding systems as appropriate for the current
+DOS codepage.
+
+@item M-x codepage-setup
+Create a coding system for a certain DOS codepage.
+@end table
+
+@cindex codepage, MS-DOS
+@cindex DOS codepages
+ MS-DOS is designed to support one character set of 256 characters at
+any given time, but gives you a variety of character sets to choose
+from. The alternative character sets are known as @dfn{DOS codepages}.
+Each codepage includes all 128 @acronym{ASCII} characters, but the other 128
+characters (codes 128 through 255) vary from one codepage to another.
+Each DOS codepage is identified by a 3-digit number, such as 850, 862,
+etc.
+
+ In contrast to X, which lets you use several fonts at the same time,
+MS-DOS normally doesn't allow use of several codepages in a single
+session. MS-DOS was designed to load a single codepage at system
+startup, and require you to reboot in order to change
+it@footnote{Normally, one particular codepage is burnt into the
+display memory, while other codepages can be installed by modifying
+system configuration files, such as @file{CONFIG.SYS}, and rebooting.
+While there is third-party software that allows changing the codepage
+without rebooting, we describe here how a stock MS-DOS system
+behaves.}. Much the same limitation applies when you run DOS
+executables on other systems such as MS-Windows.
+
+@cindex unibyte operation @r{(MS-DOS)}
+ If you invoke Emacs on MS-DOS with the @samp{--unibyte} option
+(@pxref{Initial Options,,,emacs, the Emacs Manual}), Emacs does not
+perform any conversion of non-@acronym{ASCII} characters. Instead, it
+reads and writes any non-@acronym{ASCII} characters verbatim, and
+sends their 8-bit codes to the display verbatim. Thus, unibyte Emacs
+on MS-DOS supports the current codepage, whatever it may be, but
+cannot even represent any other characters.
+
+@vindex dos-codepage
+ For multibyte operation on MS-DOS, Emacs needs to know which
+characters the chosen DOS codepage can display. So it queries the
+system shortly after startup to get the chosen codepage number, and
+stores the number in the variable @code{dos-codepage}. Some systems
+return the default value 437 for the current codepage, even though the
+actual codepage is different. (This typically happens when you use the
+codepage built into the display hardware.) You can specify a different
+codepage for Emacs to use by setting the variable @code{dos-codepage} in
+your init file.
+
+@cindex language environment, automatic selection on @r{MS-DOS}
+ Multibyte Emacs supports only certain DOS codepages: those which can
+display Far-Eastern scripts, like the Japanese codepage 932, and those
+that encode a single ISO 8859 character set.
+
+ The Far-Eastern codepages can directly display one of the MULE
+character sets for these countries, so Emacs simply sets up to use the
+appropriate terminal coding system that is supported by the codepage.
+The special features described in the rest of this section mostly
+pertain to codepages that encode ISO 8859 character sets.
+
+ For the codepages which correspond to one of the ISO character sets,
+Emacs knows the character set name based on the codepage number. Emacs
+automatically creates a coding system to support reading and writing
+files that use the current codepage, and uses this coding system by
+default. The name of this coding system is @code{cp@var{nnn}}, where
+@var{nnn} is the codepage number.@footnote{The standard Emacs coding
+systems for ISO 8859 are not quite right for the purpose, because
+typically the DOS codepage does not match the standard ISO character
+codes. For example, the letter @samp{@,{c}} (@samp{c} with cedilla) has
+code 231 in the standard Latin-1 character set, but the corresponding
+DOS codepage 850 uses code 135 for this glyph.}
+
+@cindex mode line @r{(MS-DOS)}
+ All the @code{cp@var{nnn}} coding systems use the letter @samp{D}
+(for ``DOS'') as their mode-line mnemonic. Since both the terminal
+coding system and the default coding system for file I/O are set to
+the proper @code{cp@var{nnn}} coding system at startup, it is normal
+for the mode line on MS-DOS to begin with @samp{-DD\-}. @xref{Mode
+Line,,,emacs, the Emacs Manual}. Far-Eastern DOS terminals do not use
+the @code{cp@var{nnn}} coding systems, and thus their initial mode
+line looks like the Emacs default.
+
+ Since the codepage number also indicates which script you are using,
+Emacs automatically runs @code{set-language-environment} to select the
+language environment for that script (@pxref{Language
+Environments,,,emacs, the Emacs Manual}).
+
+ If a buffer contains a character belonging to some other ISO 8859
+character set, not the one that the chosen DOS codepage supports, Emacs
+displays it using a sequence of @acronym{ASCII} characters. For example, if the
+current codepage doesn't have a glyph for the letter @samp{@`o} (small
+@samp{o} with a grave accent), it is displayed as @samp{@{`o@}}, where
+the braces serve as a visual indication that this is a single character.
+(This may look awkward for some non-Latin characters, such as those from
+Greek or Hebrew alphabets, but it is still readable by a person who
+knows the language.) Even though the character may occupy several
+columns on the screen, it is really still just a single character, and
+all Emacs commands treat it as one.
+
+@cindex IBM graphics characters (MS-DOS)
+@cindex box-drawing characters (MS-DOS)
+@cindex line-drawing characters (MS-DOS)
+ Not all characters in DOS codepages correspond to ISO 8859
+characters---some are used for other purposes, such as box-drawing
+characters and other graphics. Emacs maps these characters to two
+special character sets called @code{eight-bit-control} and
+@code{eight-bit-graphic}, and displays them as their IBM glyphs.
+However, you should be aware that other systems might display these
+characters differently, so you should avoid them in text that might be
+copied to a different operating system, or even to another DOS machine
+that uses a different codepage.
+
+@vindex dos-unsupported-character-glyph
+ Emacs supports many other characters sets aside from ISO 8859, but it
+cannot display them on MS-DOS. So if one of these multibyte characters
+appears in a buffer, Emacs on MS-DOS displays them as specified by the
+@code{dos-unsupported-character-glyph} variable; by default, this glyph
+is an empty triangle. Use the @kbd{C-u C-x =} command to display the
+actual code and character set of such characters. @xref{Position
+Info,,,emacs, the Emacs Manual}.
+
+@findex codepage-setup
+ By default, Emacs defines a coding system to support the current
+codepage. To define a coding system for some other codepage (e.g., to
+visit a file written on a DOS machine in another country), use the
+@kbd{M-x codepage-setup} command. It prompts for the 3-digit code of
+the codepage, with completion, then creates the coding system for the
+specified codepage. You can then use the new coding system to read and
+write files, but you must specify it explicitly for the file command
+when you want to use it (@pxref{Text Coding,,,emacs, the Emacs Manual}).
+
+ These coding systems are also useful for visiting a file encoded using
+a DOS codepage, using Emacs running on some other operating system.
+
+@cindex MS-Windows codepages
+ MS-Windows provides its own codepages, which are different from the
+DOS codepages for the same locale. For example, DOS codepage 850
+supports the same character set as Windows codepage 1252; DOS codepage
+855 supports the same character set as Windows codepage 1251, etc.
+The MS-Windows version of Emacs uses the current codepage for display
+when invoked with the @samp{-nw} option. Support for codepages in the
+Windows port of Emacs is part of the @file{code-pages.el} package.
+
+@node MS-DOS Processes
+@section Subprocesses on MS-DOS
+
+@cindex compilation under MS-DOS
+@cindex inferior processes under MS-DOS
+@findex compile @r{(MS-DOS)}
+@findex grep @r{(MS-DOS)}
+ Because MS-DOS is a single-process ``operating system,''
+asynchronous subprocesses are not available. In particular, Shell
+mode and its variants do not work. Most Emacs features that use
+asynchronous subprocesses also don't work on MS-DOS, including
+Shell mode and GUD. When in doubt, try and see; commands that
+don't work output an error message saying that asynchronous processes
+aren't supported.
+
+ Compilation under Emacs with @kbd{M-x compile}, searching files with
+@kbd{M-x grep} and displaying differences between files with @kbd{M-x
+diff} do work, by running the inferior processes synchronously. This
+means you cannot do any more editing until the inferior process
+finishes.
+
+ Spell checking also works, by means of special support for synchronous
+invocation of the @code{ispell} program. This is slower than the
+asynchronous invocation on other platforms
+
+ Instead of the Shell mode, which doesn't work on MS-DOS, you can use
+the @kbd{M-x eshell} command. This invokes the Eshell package that
+implements a Posix-like shell entirely in Emacs Lisp.
+
+ By contrast, Emacs compiled as a native Windows application
+@strong{does} support asynchronous subprocesses. @xref{Windows
+Processes,,,emacs, the Emacs Manual}.
+
+@cindex printing under MS-DOS
+ Printing commands, such as @code{lpr-buffer}
+(@pxref{Printing,,,emacs, the Emacs Manual}) and
+@code{ps-print-buffer} (@pxref{PostScript,,,emacs, the Emacs Manual}),
+work in MS-DOS by sending the output to one of the printer ports.
+@xref{MS-DOS Printing,,,emacs, the Emacs Manual}.
+
+ When you run a subprocess synchronously on MS-DOS, make sure the
+program terminates and does not try to read keyboard input. If the
+program does not terminate on its own, you will be unable to terminate
+it, because MS-DOS provides no general way to terminate a process.
+Pressing @kbd{C-c} or @kbd{C-@key{BREAK}} might sometimes help in these
+cases.
+
+ Accessing files on other machines is not supported on MS-DOS. Other
+network-oriented commands such as sending mail, Web browsing, remote
+login, etc., don't work either, unless network access is built into
+MS-DOS with some network redirector.
+
+@cindex directory listing on MS-DOS
+@vindex dired-listing-switches @r{(MS-DOS)}
+ Dired on MS-DOS uses the @code{ls-lisp} package where other
+platforms use the system @code{ls} command. Therefore, Dired on
+MS-DOS supports only some of the possible options you can mention in
+the @code{dired-listing-switches} variable. The options that work are
+@samp{-A}, @samp{-a}, @samp{-c}, @samp{-i}, @samp{-r}, @samp{-S},
+@samp{-s}, @samp{-t}, and @samp{-u}.
+
+
@node Index
@unnumbered Index
-@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
-@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
-@c See file emacs.texi for copying conditions.
-@node MS-DOS, Manifesto, Mac OS, Top
-@appendix Emacs and Microsoft Systems
-@cindex MS-DOG
-@cindex Microsoft Windows
-@cindex MS-DOS peculiarities
-
- This section briefly describes the peculiarities of using Emacs on
-the MS-DOS ``operating system'' (also known as ``MS-DOG'') and on
-Microsoft Windows.
-
- If you build Emacs for MS-DOS, the binary will also run on Windows
-3.X, Windows NT, Windows 9X/ME, Windows 2000, or OS/2 as a DOS
-application; all the of this chapter applies for all of those systems,
-if you use an Emacs that was built for MS-DOS.
-
- However, if you want to use Emacs on Windows, you would normally
-build Emacs specifically for Windows. If you do that, most of this
-chapter does not apply; instead, you get behavior much closer to what
-is documented in the rest of the manual, including support for long
-file names, multiple frames, scroll bars, mouse menus, and
-subprocesses. However, the section on text files and binary files
-does still apply. There are also two sections at the end of this
-chapter which apply specifically for the Windows version.
-
-@menu
-* Keyboard: MS-DOS Keyboard. Keyboard conventions on MS-DOS.
-* Mouse: MS-DOS Mouse. Mouse conventions on MS-DOS.
-* Display: MS-DOS Display. Fonts, frames and display size on MS-DOS.
-* Files: MS-DOS File Names. File name conventions on MS-DOS.
-* Text and Binary:: Text files on MS-DOS use CRLF to separate lines.
-* Printing: MS-DOS Printing. How to specify the printer on MS-DOS.
-* I18N: MS-DOS and MULE. Support for internationalization on MS-DOS.
-* Processes: MS-DOS Processes. Running subprocesses on MS-DOS.
-* Windows Processes:: Running subprocesses on Windows.
-* Windows System Menu:: Controlling what the ALT key does.
-@end menu
-
-@node MS-DOS Keyboard
-@section Keyboard Usage on MS-DOS
-
-@kindex DEL @r{(MS-DOS)}
-@kindex BS @r{(MS-DOS)}
- The key that is called @key{DEL} in Emacs (because that's how it is
-designated on most workstations) is known as @key{BS} (backspace) on a
-PC. That is why the PC-specific terminal initialization remaps the
-@key{BS} key to act as @key{DEL}; the @key{DELETE} key is remapped to act
-as @kbd{C-d} for the same reasons.
-
-@kindex C-g @r{(MS-DOS)}
-@kindex C-BREAK @r{(MS-DOS)}
-@cindex quitting on MS-DOS
- Emacs built for MS-DOS recognizes @kbd{C-@key{BREAK}} as a quit
-character, just like @kbd{C-g}. This is because Emacs cannot detect
-that you have typed @kbd{C-g} until it is ready for more input. As a
-consequence, you cannot use @kbd{C-g} to stop a running command
-(@pxref{Quitting}). By contrast, @kbd{C-@key{BREAK}} @emph{is} detected
-as soon as you type it (as @kbd{C-g} is on other systems), so it can be
-used to stop a running command and for emergency escape
-(@pxref{Emergency Escape}).
-
-@cindex Meta (under MS-DOS)
-@cindex Hyper (under MS-DOS)
-@cindex Super (under MS-DOS)
-@vindex dos-super-key
-@vindex dos-hyper-key
- The PC keyboard maps use the left @key{ALT} key as the @key{META} key.
-You have two choices for emulating the @key{SUPER} and @key{HYPER} keys:
-choose either the right @key{CTRL} key or the right @key{ALT} key by
-setting the variables @code{dos-hyper-key} and @code{dos-super-key} to 1
-or 2 respectively. If neither @code{dos-super-key} nor
-@code{dos-hyper-key} is 1, then by default the right @key{ALT} key is
-also mapped to the @key{META} key. However, if the MS-DOS international
-keyboard support program @file{KEYB.COM} is installed, Emacs will
-@emph{not} map the right @key{ALT} to @key{META}, since it is used for
-accessing characters like @kbd{~} and @kbd{@@} on non-US keyboard
-layouts; in this case, you may only use the left @key{ALT} as @key{META}
-key.
-
-@kindex C-j @r{(MS-DOS)}
-@vindex dos-keypad-mode
- The variable @code{dos-keypad-mode} is a flag variable that controls
-what key codes are returned by keys in the numeric keypad. You can also
-define the keypad @key{ENTER} key to act like @kbd{C-j}, by putting the
-following line into your @file{_emacs} file:
-
-@smallexample
-;; @r{Make the @key{ENTER} key from the numeric keypad act as @kbd{C-j}.}
-(define-key function-key-map [kp-enter] [?\C-j])
-@end smallexample
-
-@node MS-DOS Mouse
-@section Mouse Usage on MS-DOS
-
-@cindex mouse support under MS-DOS
- Emacs on MS-DOS supports a mouse (on the default terminal only).
-The mouse commands work as documented, including those that use menus
-and the menu bar (@pxref{Menu Bar}). Scroll bars don't work in
-MS-DOS Emacs. PC mice usually have only two buttons; these act as
-@kbd{Mouse-1} and @kbd{Mouse-2}, but if you press both of them
-together, that has the effect of @kbd{Mouse-3}. If the mouse does have
-3 buttons, Emacs detects that at startup, and all the 3 buttons function
-normally, as on X.
-
- Help strings for menu-bar and pop-up menus are displayed in the echo
-area when the mouse pointer moves across the menu items.
-Highlighting of mouse-sensitive text (@pxref{Mouse References}) is also
-supported.
-
-@cindex mouse, set number of buttons
-@findex msdos-set-mouse-buttons
- Some versions of mouse drivers don't report the number of mouse
-buttons correctly. For example, mice with a wheel report that they
-have 3 buttons, but only 2 of them are passed to Emacs; the clicks on
-the wheel, which serves as the middle button, are not passed. In
-these cases, you can use the @kbd{M-x msdos-set-mouse-buttons} command
-to tell Emacs how many mouse buttons to expect. You could make such a
-setting permanent by adding this fragment to your @file{_emacs} init
-file:
-
-@example
-;; @r{Treat the mouse like a 2-button mouse.}
-(msdos-set-mouse-buttons 2)
-@end example
-
-@cindex Windows clipboard support
- Emacs built for MS-DOS supports clipboard operations when it runs on
-Windows. Commands that put text on the kill ring, or yank text from the
-ring, check the Windows clipboard first, just as Emacs does on the X
-Window System (@pxref{Mouse Commands}). Only the primary selection and
-the cut buffer are supported by MS-DOS Emacs on Windows; the secondary
-selection always appears as empty.
-
- Due to the way clipboard access is implemented by Windows, the
-length of text you can put into the clipboard is limited by the amount
-of free DOS memory that is available to Emacs. Usually, up to 620KB of
-text can be put into the clipboard, but this limit depends on the system
-configuration and is lower if you run Emacs as a subprocess of
-another program. If the killed text does not fit, Emacs outputs a
-message saying so, and does not put the text into the clipboard.
-
- Null characters also cannot be put into the Windows clipboard. If the
-killed text includes null characters, Emacs does not put such text into
-the clipboard, and displays in the echo area a message to that effect.
-
-@vindex dos-display-scancodes
- The variable @code{dos-display-scancodes}, when non-@code{nil},
-directs Emacs to display the @acronym{ASCII} value and the keyboard scan code of
-each keystroke; this feature serves as a complement to the
-@code{view-lossage} command, for debugging.
-
-@node MS-DOS Display
-@section Display on MS-DOS
-@cindex faces under MS-DOS
-@cindex fonts, emulating under MS-DOS
-
- Display on MS-DOS cannot use font variants, like bold or italic,
-but it does support
-multiple faces, each of which can specify a foreground and a background
-color. Therefore, you can get the full functionality of Emacs packages
-that use fonts (such as @code{font-lock}, Enriched Text mode, and
-others) by defining the relevant faces to use different colors. Use the
-@code{list-colors-display} command (@pxref{Frame Parameters}) and the
-@code{list-faces-display} command (@pxref{Faces}) to see what colors and
-faces are available and what they look like.
-
- @xref{MS-DOS and MULE}, later in this chapter, for information on
-how Emacs displays glyphs and characters that aren't supported by the
-native font built into the DOS display.
-
-@cindex cursor shape on MS-DOS
- When Emacs starts, it changes the cursor shape to a solid box. This
-is for compatibility with other systems, where the box cursor is the
-default in Emacs. This default shape can be changed to a bar by
-specifying the @code{cursor-type} parameter in the variable
-@code{default-frame-alist} (@pxref{Creating Frames}). The MS-DOS
-terminal doesn't support a vertical-bar cursor, so the bar cursor is
-horizontal, and the @code{@var{width}} parameter, if specified by the
-frame parameters, actually determines its height. For this reason,
-the @code{bar} and @code{hbar} cursor types produce the same effect on
-MS-DOS. As an extension, the bar cursor specification can include the
-starting scan line of the cursor as well as its width, like this:
-
-@example
- '(cursor-type bar @var{width} . @var{start})
-@end example
-
-@noindent
-In addition, if the @var{width} parameter is negative, the cursor bar
-begins at the top of the character cell.
-
-@cindex frames on MS-DOS
- The MS-DOS terminal can only display a single frame at a time. The
-Emacs frame facilities work on MS-DOS much as they do on text-only
-terminals (@pxref{Frames}). When you run Emacs from a DOS window on
-MS-Windows, you can make the visible frame smaller than the full
-screen, but Emacs still cannot display more than a single frame at a
-time.
-
-@cindex frame size under MS-DOS
-@findex mode4350
-@findex mode25
- The @code{mode4350} command switches the display to 43 or 50
-lines, depending on your hardware; the @code{mode25} command switches
-to the default 80x25 screen size.
-
- By default, Emacs only knows how to set screen sizes of 80 columns by
-25, 28, 35, 40, 43 or 50 rows. However, if your video adapter has
-special video modes that will switch the display to other sizes, you can
-have Emacs support those too. When you ask Emacs to switch the frame to
-@var{n} rows by @var{m} columns dimensions, it checks if there is a
-variable called @code{screen-dimensions-@var{n}x@var{m}}, and if so,
-uses its value (which must be an integer) as the video mode to switch
-to. (Emacs switches to that video mode by calling the BIOS @code{Set
-Video Mode} function with the value of
-@code{screen-dimensions-@var{n}x@var{m}} in the @code{AL} register.)
-For example, suppose your adapter will switch to 66x80 dimensions when
-put into video mode 85. Then you can make Emacs support this screen
-size by putting the following into your @file{_emacs} file:
-
-@example
-(setq screen-dimensions-66x80 85)
-@end example
-
- Since Emacs on MS-DOS can only set the frame size to specific
-supported dimensions, it cannot honor every possible frame resizing
-request. When an unsupported size is requested, Emacs chooses the next
-larger supported size beyond the specified size. For example, if you
-ask for 36x80 frame, you will get 40x80 instead.
-
- The variables @code{screen-dimensions-@var{n}x@var{m}} are used only
-when they exactly match the specified size; the search for the next
-larger supported size ignores them. In the above example, even if your
-VGA supports 38x80 dimensions and you define a variable
-@code{screen-dimensions-38x80} with a suitable value, you will still get
-40x80 screen when you ask for a 36x80 frame. If you want to get the
-38x80 size in this case, you can do it by setting the variable named
-@code{screen-dimensions-36x80} with the same video mode value as
-@code{screen-dimensions-38x80}.
-
- Changing frame dimensions on MS-DOS has the effect of changing all the
-other frames to the new dimensions.
-
-@node MS-DOS File Names
-@section File Names on MS-DOS
-@cindex file names under MS-DOS
-@cindex init file, default name under MS-DOS
-
- MS-DOS normally uses a backslash, @samp{\}, to separate name units
-within a file name, instead of the slash used on other systems. Emacs
-on MS-DOS permits use of either slash or backslash, and also knows
-about drive letters in file names.
-
- On MS-DOS, file names are case-insensitive and limited to eight
-characters, plus optionally a period and three more characters. Emacs
-knows enough about these limitations to handle file names that were
-meant for other operating systems. For instance, leading dots @samp{.}
-in file names are invalid in MS-DOS, so Emacs transparently converts
-them to underscores @samp{_}; thus your default init file (@pxref{Init
-File}) is called @file{_emacs} on MS-DOS. Excess characters before or
-after the period are generally ignored by MS-DOS itself; thus, if you
-visit the file @file{LongFileName.EvenLongerExtension}, you will
-silently get @file{longfile.eve}, but Emacs will still display the long
-file name on the mode line. Other than that, it's up to you to specify
-file names which are valid under MS-DOS; the transparent conversion as
-described above only works on file names built into Emacs.
-
-@cindex backup file names on MS-DOS
- The above restrictions on the file names on MS-DOS make it almost
-impossible to construct the name of a backup file (@pxref{Backup
-Names}) without losing some of the original file name characters. For
-example, the name of a backup file for @file{docs.txt} is
-@file{docs.tx~} even if single backup is used.
-
-@cindex file names under Windows 95/NT
-@cindex long file names in DOS box under Windows 95/NT
- If you run Emacs as a DOS application under Windows 9X, Windows ME, or
-Windows 2000, you can turn on support for long file names. If you do
-that, Emacs doesn't truncate file names or convert them to lower case;
-instead, it uses the file names that you specify, verbatim. To enable
-long file name support, set the environment variable @env{LFN} to
-@samp{y} before starting Emacs. Unfortunately, Windows NT doesn't allow
-DOS programs to access long file names, so Emacs built for MS-DOS will
-only see their short 8+3 aliases.
-
-@cindex @env{HOME} directory under MS-DOS
- MS-DOS has no notion of home directory, so Emacs on MS-DOS pretends
-that the directory where it is installed is the value of the @env{HOME}
-environment variable. That is, if your Emacs binary,
-@file{emacs.exe}, is in the directory @file{c:/utils/emacs/bin}, then
-Emacs acts as if @env{HOME} were set to @samp{c:/utils/emacs}. In
-particular, that is where Emacs looks for the init file @file{_emacs}.
-With this in mind, you can use @samp{~} in file names as an alias for
-the home directory, as you would on GNU or Unix. You can also set
-@env{HOME} variable in the environment before starting Emacs; its
-value will then override the above default behavior.
-
- Emacs on MS-DOS handles the directory name @file{/dev} specially,
-because of a feature in the emulator libraries of DJGPP that pretends
-I/O devices have names in that directory. We recommend that you avoid
-using an actual directory named @file{/dev} on any disk.
-
-@node Text and Binary
-@section Text Files and Binary Files
-@cindex text and binary files on MS-DOS/MS-Windows
-
- GNU Emacs uses newline characters to separate text lines. This is the
-convention used on GNU and Unix.
-
-@cindex end-of-line conversion on MS-DOS/MS-Windows
- MS-DOS and MS-Windows normally use carriage-return linefeed, a
-two-character sequence, to separate text lines. (Linefeed is the same
-character as newline.) Therefore, convenient editing of typical files
-with Emacs requires conversion of these end-of-line (EOL) sequences.
-And that is what Emacs normally does: it converts carriage-return
-linefeed into newline when reading files, and converts newline into
-carriage-return linefeed when writing files. The same mechanism that
-handles conversion of international character codes does this conversion
-also (@pxref{Coding Systems}).
-
-@cindex cursor location, on MS-DOS
-@cindex point location, on MS-DOS
- One consequence of this special format-conversion of most files is
-that character positions as reported by Emacs (@pxref{Position Info}) do
-not agree with the file size information known to the operating system.
-
- In addition, if Emacs recognizes from a file's contents that it uses
-newline rather than carriage-return linefeed as its line separator, it
-does not perform EOL conversion when reading or writing that file.
-Thus, you can read and edit files from GNU and Unix systems on MS-DOS
-with no special effort, and they will retain their Unix-style
-end-of-line convention after you edit them.
-
- The mode line indicates whether end-of-line translation was used for
-the current buffer. If MS-DOS end-of-line translation is in use for the
-buffer, a backslash @samp{\} is displayed after the coding system
-mnemonic near the beginning of the mode line (@pxref{Mode Line}). If no
-EOL translation was performed, the string @samp{(Unix)} is displayed
-instead of the backslash, to alert you that the file's EOL format is not
-the usual carriage-return linefeed.
-
-@cindex DOS-to-Unix conversion of files
- To visit a file and specify whether it uses DOS-style or Unix-style
-end-of-line, specify a coding system (@pxref{Text Coding}). For
-example, @kbd{C-x @key{RET} c unix @key{RET} C-x C-f foobar.txt}
-visits the file @file{foobar.txt} without converting the EOLs; if some
-line ends with a carriage-return linefeed pair, Emacs will display
-@samp{^M} at the end of that line. Similarly, you can direct Emacs to
-save a buffer in a specified EOL format with the @kbd{C-x @key{RET} f}
-command. For example, to save a buffer with Unix EOL format, type
-@kbd{C-x @key{RET} f unix @key{RET} C-x C-s}. If you visit a file
-with DOS EOL conversion, then save it with Unix EOL format, that
-effectively converts the file to Unix EOL style, like @code{dos2unix}.
-
-@cindex untranslated file system
-@findex add-untranslated-filesystem
- When you use NFS or Samba to access file systems that reside on
-computers using GNU or Unix systems, Emacs should not perform
-end-of-line translation on any files in these file systems---not even
-when you create a new file. To request this, designate these file
-systems as @dfn{untranslated} file systems by calling the function
-@code{add-untranslated-filesystem}. It takes one argument: the file
-system name, including a drive letter and optionally a directory. For
-example,
-
-@example
-(add-untranslated-filesystem "Z:")
-@end example
-
-@noindent
-designates drive Z as an untranslated file system, and
-
-@example
-(add-untranslated-filesystem "Z:\\foo")
-@end example
-
-@noindent
-designates directory @file{\foo} on drive Z as an untranslated file
-system.
-
- Most often you would use @code{add-untranslated-filesystem} in your
-@file{_emacs} file, or in @file{site-start.el} so that all the users at
-your site get the benefit of it.
-
-@findex remove-untranslated-filesystem
- To countermand the effect of @code{add-untranslated-filesystem}, use
-the function @code{remove-untranslated-filesystem}. This function takes
-one argument, which should be a string just like the one that was used
-previously with @code{add-untranslated-filesystem}.
-
- Designating a file system as untranslated does not affect character
-set conversion, only end-of-line conversion. Essentially, it directs
-Emacs to create new files with the Unix-style convention of using
-newline at the end of a line. @xref{Coding Systems}.
-
-@vindex file-name-buffer-file-type-alist
-@cindex binary files, on MS-DOS/MS-Windows
- Some kinds of files should not be converted at all, because their
-contents are not really text. Therefore, Emacs on MS-DOS distinguishes
-certain files as @dfn{binary files}. (This distinction is not part of
-MS-DOS; it is made by Emacs only.) Binary files include executable
-programs, compressed archives, etc. Emacs uses the file name to decide
-whether to treat a file as binary: the variable
-@code{file-name-buffer-file-type-alist} defines the file-name patterns
-that indicate binary files. If a file name matches one of the patterns
-for binary files (those whose associations are of the type
-@code{(@var{pattern} . t)}, Emacs reads and writes that file using the
-@code{no-conversion} coding system (@pxref{Coding Systems}) which turns
-off @emph{all} coding-system conversions, not only the EOL conversion.
-@code{file-name-buffer-file-type-alist} also includes file-name patterns
-for files which are known to be DOS-style text files with
-carriage-return linefeed EOL format, such as @file{CONFIG.SYS}; Emacs
-always writes those files with DOS-style EOLs.
-
- If a file which belongs to an untranslated file system matches one of
-the file-name patterns in @code{file-name-buffer-file-type-alist}, the
-EOL conversion is determined by @code{file-name-buffer-file-type-alist}.
-
-@node MS-DOS Printing
-@section Printing and MS-DOS
-
- Printing commands, such as @code{lpr-buffer} (@pxref{Printing}) and
-@code{ps-print-buffer} (@pxref{PostScript}) can work in MS-DOS and
-MS-Windows by sending the output to one of the printer ports, if a
-Posix-style @code{lpr} program is unavailable. The same Emacs
-variables control printing on all systems, but in some cases they have
-different default values on MS-DOS and MS-Windows.
-
-@vindex printer-name @r{(MS-DOS)}
- If you want to use your local printer, printing on it in the usual DOS
-manner, then set the Lisp variable @code{lpr-command} to @code{""} (its
-default value) and @code{printer-name} to the name of the printer
-port---for example, @code{"PRN"}, the usual local printer port (that's
-the default), or @code{"LPT2"}, or @code{"COM1"} for a serial printer.
-You can also set @code{printer-name} to a file name, in which case
-``printed'' output is actually appended to that file. If you set
-@code{printer-name} to @code{"NUL"}, printed output is silently
-discarded (sent to the system null device).
-
- On MS-Windows, when the Windows network software is installed, you can
-also use a printer shared by another machine by setting
-@code{printer-name} to the UNC share name for that printer---for example,
-@code{"//joes_pc/hp4si"}. (It doesn't matter whether you use forward
-slashes or backslashes here.) To find out the names of shared printers,
-run the command @samp{net view} at a DOS command prompt to obtain a list
-of servers, and @samp{net view @var{server-name}} to see the names of printers
-(and directories) shared by that server. Alternatively, click the
-@samp{Network Neighborhood} icon on your desktop, and look for machines
-which share their printers via the network.
-
-@cindex @samp{net use}, and printing on MS-Windows
-@cindex networked printers (MS-Windows)
- If the printer doesn't appear in the output of @samp{net view}, or
-if setting @code{printer-name} to the UNC share name doesn't produce a
-hardcopy on that printer, you can use the @samp{net use} command to
-connect a local print port such as @code{"LPT2"} to the networked
-printer. For example, typing @kbd{net use LPT2:
-\\joes_pc\hp4si}@footnote{
-Note that the @samp{net use} command requires the UNC share name to be
-typed with the Windows-style backslashes, while the value of
-@code{printer-name} can be set with either forward- or backslashes.}
-causes Windows to @dfn{capture} the LPT2 port and redirect the printed
-material to the printer connected to the machine @code{joes_pc}.
-After this command, setting @code{printer-name} to @code{"LPT2"}
-should produce the hardcopy on the networked printer.
-
- With some varieties of Windows network software, you can instruct
-Windows to capture a specific printer port such as @code{"LPT2"}, and
-redirect it to a networked printer via the @w{@code{Control
-Panel->Printers}} applet instead of @samp{net use}.
-
- Some printers expect DOS codepage encoding of non-@acronym{ASCII} text, even
-though they are connected to a Windows machine which uses a different
-encoding for the same locale. For example, in the Latin-1 locale, DOS
-uses codepage 850 whereas Windows uses codepage 1252. @xref{MS-DOS and
-MULE}. When you print to such printers from Windows, you can use the
-@kbd{C-x RET c} (@code{universal-coding-system-argument}) command before
-@kbd{M-x lpr-buffer}; Emacs will then convert the text to the DOS
-codepage that you specify. For example, @kbd{C-x RET c cp850-dos RET
-M-x lpr-region RET} will print the region while converting it to the
-codepage 850 encoding. You may need to create the @code{cp@var{nnn}}
-coding system with @kbd{M-x codepage-setup}.
-
- If you set @code{printer-name} to a file name, it's best to use an
-absolute file name. Emacs changes the working directory according to
-the default directory of the current buffer, so if the file name in
-@code{printer-name} is relative, you will end up with several such
-files, each one in the directory of the buffer from which the printing
-was done.
-
-@findex print-buffer @r{(MS-DOS)}
-@findex print-region @r{(MS-DOS)}
-@vindex lpr-headers-switches @r{(MS-DOS)}
- The commands @code{print-buffer} and @code{print-region} call the
-@code{pr} program, or use special switches to the @code{lpr} program, to
-produce headers on each printed page. MS-DOS and MS-Windows don't
-normally have these programs, so by default, the variable
-@code{lpr-headers-switches} is set so that the requests to print page
-headers are silently ignored. Thus, @code{print-buffer} and
-@code{print-region} produce the same output as @code{lpr-buffer} and
-@code{lpr-region}, respectively. If you do have a suitable @code{pr}
-program (for example, from GNU Textutils), set
-@code{lpr-headers-switches} to @code{nil}; Emacs will then call
-@code{pr} to produce the page headers, and print the resulting output as
-specified by @code{printer-name}.
-
-@vindex print-region-function @r{(MS-DOS)}
-@cindex lpr usage under MS-DOS
-@vindex lpr-command @r{(MS-DOS)}
-@vindex lpr-switches @r{(MS-DOS)}
- Finally, if you do have an @code{lpr} work-alike, you can set the
-variable @code{lpr-command} to @code{"lpr"}. Then Emacs will use
-@code{lpr} for printing, as on other systems. (If the name of the
-program isn't @code{lpr}, set @code{lpr-command} to specify where to
-find it.) The variable @code{lpr-switches} has its standard meaning
-when @code{lpr-command} is not @code{""}. If the variable
-@code{printer-name} has a string value, it is used as the value for the
-@code{-P} option to @code{lpr}, as on Unix.
-
-@findex ps-print-buffer @r{(MS-DOS)}
-@findex ps-spool-buffer @r{(MS-DOS)}
-@vindex ps-printer-name @r{(MS-DOS)}
-@vindex ps-lpr-command @r{(MS-DOS)}
-@vindex ps-lpr-switches @r{(MS-DOS)}
- A parallel set of variables, @code{ps-lpr-command},
-@code{ps-lpr-switches}, and @code{ps-printer-name} (@pxref{PostScript
-Variables}), defines how PostScript files should be printed. These
-variables are used in the same way as the corresponding variables
-described above for non-PostScript printing. Thus, the value of
-@code{ps-printer-name} is used as the name of the device (or file) to
-which PostScript output is sent, just as @code{printer-name} is used for
-non-PostScript printing. (There are two distinct sets of variables in
-case you have two printers attached to two different ports, and only one
-of them is a PostScript printer.)
-
- The default value of the variable @code{ps-lpr-command} is @code{""},
-which causes PostScript output to be sent to the printer port specified
-by @code{ps-printer-name}, but @code{ps-lpr-command} can also be set to
-the name of a program which will accept PostScript files. Thus, if you
-have a non-PostScript printer, you can set this variable to the name of
-a PostScript interpreter program (such as Ghostscript). Any switches
-that need to be passed to the interpreter program are specified using
-@code{ps-lpr-switches}. (If the value of @code{ps-printer-name} is a
-string, it will be added to the list of switches as the value for the
-@code{-P} option. This is probably only useful if you are using
-@code{lpr}, so when using an interpreter typically you would set
-@code{ps-printer-name} to something other than a string so it is
-ignored.)
-
- For example, to use Ghostscript for printing on an Epson printer
-connected to the @samp{LPT2} port, put this in your @file{_emacs} file:
-
-@example
-(setq ps-printer-name t) ; Ghostscript doesn't understand -P
-(setq ps-lpr-command "c:/gs/gs386")
-(setq ps-lpr-switches '("-q" "-dNOPAUSE"
- "-sDEVICE=epson"
- "-r240x72"
- "-sOutputFile=LPT2"
- "-Ic:/gs"))
-@end example
-
-@noindent
-(This assumes that Ghostscript is installed in the @file{"c:/gs"}
-directory.)
-
-@vindex dos-printer
-@vindex dos-ps-printer
- For backwards compatibility, the value of @code{dos-printer}
-(@code{dos-ps-printer}), if it has a value, overrides the value of
-@code{printer-name} (@code{ps-printer-name}), on MS-DOS and MS-Windows
-only.
-
-
-@node MS-DOS and MULE
-@section International Support on MS-DOS
-@cindex international support @r{(MS-DOS)}
-
- Emacs on MS-DOS supports the same international character sets as it
-does on GNU, Unix and other platforms (@pxref{International}), including
-coding systems for converting between the different character sets.
-However, due to incompatibilities between MS-DOS/MS-Windows and other systems,
-there are several DOS-specific aspects of this support that you should
-be aware of. This section describes these aspects.
-
- The description below is largely specific to the MS-DOS port of
-Emacs, especially where it talks about practical implications for
-Emacs users. For other operating systems, see the @file{code-pages.el}
-package, which implements support for MS-DOS- and MS-Windows-specific
-encodings for all platforms other than MS-DOS.
-
-@table @kbd
-@item M-x dos-codepage-setup
-Set up Emacs display and coding systems as appropriate for the current
-DOS codepage.
-
-@item M-x codepage-setup
-Create a coding system for a certain DOS codepage.
-@end table
-
-@cindex codepage, MS-DOS
-@cindex DOS codepages
- MS-DOS is designed to support one character set of 256 characters at
-any given time, but gives you a variety of character sets to choose
-from. The alternative character sets are known as @dfn{DOS codepages}.
-Each codepage includes all 128 @acronym{ASCII} characters, but the other 128
-characters (codes 128 through 255) vary from one codepage to another.
-Each DOS codepage is identified by a 3-digit number, such as 850, 862,
-etc.
-
- In contrast to X, which lets you use several fonts at the same time,
-MS-DOS normally doesn't allow use of several codepages in a single
-session. MS-DOS was designed to load a single codepage at system
-startup, and require you to reboot in order to change
-it@footnote{Normally, one particular codepage is burnt into the
-display memory, while other codepages can be installed by modifying
-system configuration files, such as @file{CONFIG.SYS}, and rebooting.
-While there is third-party software that allows changing the codepage
-without rebooting, we describe here how a stock MS-DOS system
-behaves.}. Much the same limitation applies when you run DOS
-executables on other systems such as MS-Windows.
-
-@cindex unibyte operation @r{(MS-DOS)}
- If you invoke Emacs on MS-DOS with the @samp{--unibyte} option
-(@pxref{Initial Options}), Emacs does not perform any conversion of
-non-@acronym{ASCII} characters. Instead, it reads and writes any non-@acronym{ASCII}
-characters verbatim, and sends their 8-bit codes to the display
-verbatim. Thus, unibyte Emacs on MS-DOS supports the current codepage,
-whatever it may be, but cannot even represent any other characters.
-
-@vindex dos-codepage
- For multibyte operation on MS-DOS, Emacs needs to know which
-characters the chosen DOS codepage can display. So it queries the
-system shortly after startup to get the chosen codepage number, and
-stores the number in the variable @code{dos-codepage}. Some systems
-return the default value 437 for the current codepage, even though the
-actual codepage is different. (This typically happens when you use the
-codepage built into the display hardware.) You can specify a different
-codepage for Emacs to use by setting the variable @code{dos-codepage} in
-your init file.
-
-@cindex language environment, automatic selection on @r{MS-DOS}
- Multibyte Emacs supports only certain DOS codepages: those which can
-display Far-Eastern scripts, like the Japanese codepage 932, and those
-that encode a single ISO 8859 character set.
-
- The Far-Eastern codepages can directly display one of the MULE
-character sets for these countries, so Emacs simply sets up to use the
-appropriate terminal coding system that is supported by the codepage.
-The special features described in the rest of this section mostly
-pertain to codepages that encode ISO 8859 character sets.
-
- For the codepages which correspond to one of the ISO character sets,
-Emacs knows the character set name based on the codepage number. Emacs
-automatically creates a coding system to support reading and writing
-files that use the current codepage, and uses this coding system by
-default. The name of this coding system is @code{cp@var{nnn}}, where
-@var{nnn} is the codepage number.@footnote{The standard Emacs coding
-systems for ISO 8859 are not quite right for the purpose, because
-typically the DOS codepage does not match the standard ISO character
-codes. For example, the letter @samp{@,{c}} (@samp{c} with cedilla) has
-code 231 in the standard Latin-1 character set, but the corresponding
-DOS codepage 850 uses code 135 for this glyph.}
-
-@cindex mode line @r{(MS-DOS)}
- All the @code{cp@var{nnn}} coding systems use the letter @samp{D} (for
-``DOS'') as their mode-line mnemonic. Since both the terminal coding
-system and the default coding system for file I/O are set to the proper
-@code{cp@var{nnn}} coding system at startup, it is normal for the mode
-line on MS-DOS to begin with @samp{-DD\-}. @xref{Mode Line}.
-Far-Eastern DOS terminals do not use the @code{cp@var{nnn}} coding
-systems, and thus their initial mode line looks like the Emacs default.
-
- Since the codepage number also indicates which script you are using,
-Emacs automatically runs @code{set-language-environment} to select the
-language environment for that script (@pxref{Language Environments}).
-
- If a buffer contains a character belonging to some other ISO 8859
-character set, not the one that the chosen DOS codepage supports, Emacs
-displays it using a sequence of @acronym{ASCII} characters. For example, if the
-current codepage doesn't have a glyph for the letter @samp{@`o} (small
-@samp{o} with a grave accent), it is displayed as @samp{@{`o@}}, where
-the braces serve as a visual indication that this is a single character.
-(This may look awkward for some non-Latin characters, such as those from
-Greek or Hebrew alphabets, but it is still readable by a person who
-knows the language.) Even though the character may occupy several
-columns on the screen, it is really still just a single character, and
-all Emacs commands treat it as one.
-
-@cindex IBM graphics characters (MS-DOS)
-@cindex box-drawing characters (MS-DOS)
-@cindex line-drawing characters (MS-DOS)
- Not all characters in DOS codepages correspond to ISO 8859
-characters---some are used for other purposes, such as box-drawing
-characters and other graphics. Emacs maps these characters to two
-special character sets called @code{eight-bit-control} and
-@code{eight-bit-graphic}, and displays them as their IBM glyphs.
-However, you should be aware that other systems might display these
-characters differently, so you should avoid them in text that might be
-copied to a different operating system, or even to another DOS machine
-that uses a different codepage.
-
-@vindex dos-unsupported-character-glyph
- Emacs supports many other characters sets aside from ISO 8859, but it
-cannot display them on MS-DOS. So if one of these multibyte characters
-appears in a buffer, Emacs on MS-DOS displays them as specified by the
-@code{dos-unsupported-character-glyph} variable; by default, this glyph
-is an empty triangle. Use the @kbd{C-u C-x =} command to display the
-actual code and character set of such characters. @xref{Position Info}.
-
-@findex codepage-setup
- By default, Emacs defines a coding system to support the current
-codepage. To define a coding system for some other codepage (e.g., to
-visit a file written on a DOS machine in another country), use the
-@kbd{M-x codepage-setup} command. It prompts for the 3-digit code of
-the codepage, with completion, then creates the coding system for the
-specified codepage. You can then use the new coding system to read and
-write files, but you must specify it explicitly for the file command
-when you want to use it (@pxref{Text Coding}).
-
- These coding systems are also useful for visiting a file encoded using
-a DOS codepage, using Emacs running on some other operating system.
-
-@cindex MS-Windows codepages
- MS-Windows provides its own codepages, which are different from the
-DOS codepages for the same locale. For example, DOS codepage 850
-supports the same character set as Windows codepage 1252; DOS codepage
-855 supports the same character set as Windows codepage 1251, etc.
-The MS-Windows version of Emacs uses the current codepage for display
-when invoked with the @samp{-nw} option. Support for codepages in the
-Windows port of Emacs is part of the @file{code-pages.el} package.
-
-@node MS-DOS Processes
-@section Subprocesses on MS-DOS
-
-@cindex compilation under MS-DOS
-@cindex inferior processes under MS-DOS
-@findex compile @r{(MS-DOS)}
-@findex grep @r{(MS-DOS)}
- Because MS-DOS is a single-process ``operating system,''
-asynchronous subprocesses are not available. In particular, Shell
-mode and its variants do not work. Most Emacs features that use
-asynchronous subprocesses also don't work on MS-DOS, including
-Shell mode and GUD. When in doubt, try and see; commands that
-don't work output an error message saying that asynchronous processes
-aren't supported.
-
- Compilation under Emacs with @kbd{M-x compile}, searching files with
-@kbd{M-x grep} and displaying differences between files with @kbd{M-x
-diff} do work, by running the inferior processes synchronously. This
-means you cannot do any more editing until the inferior process
-finishes.
-
- Spell checking also works, by means of special support for synchronous
-invocation of the @code{ispell} program. This is slower than the
-asynchronous invocation on other platforms
-
- Instead of the Shell mode, which doesn't work on MS-DOS, you can use
-the @kbd{M-x eshell} command. This invokes the Eshell package that
-implements a Posix-like shell entirely in Emacs Lisp.
-
- By contrast, Emacs compiled as a native Windows application
-@strong{does} support asynchronous subprocesses. @xref{Windows
-Processes}.
-
-@cindex printing under MS-DOS
- Printing commands, such as @code{lpr-buffer} (@pxref{Printing}) and
-@code{ps-print-buffer} (@pxref{PostScript}), work in MS-DOS by sending
-the output to one of the printer ports. @xref{MS-DOS Printing}.
-
- When you run a subprocess synchronously on MS-DOS, make sure the
-program terminates and does not try to read keyboard input. If the
-program does not terminate on its own, you will be unable to terminate
-it, because MS-DOS provides no general way to terminate a process.
-Pressing @kbd{C-c} or @kbd{C-@key{BREAK}} might sometimes help in these
-cases.
-
- Accessing files on other machines is not supported on MS-DOS. Other
-network-oriented commands such as sending mail, Web browsing, remote
-login, etc., don't work either, unless network access is built into
-MS-DOS with some network redirector.
-
-@cindex directory listing on MS-DOS
-@vindex dired-listing-switches @r{(MS-DOS)}
- Dired on MS-DOS uses the @code{ls-lisp} package where other
-platforms use the system @code{ls} command. Therefore, Dired on
-MS-DOS supports only some of the possible options you can mention in
-the @code{dired-listing-switches} variable. The options that work are
-@samp{-A}, @samp{-a}, @samp{-c}, @samp{-i}, @samp{-r}, @samp{-S},
-@samp{-s}, @samp{-t}, and @samp{-u}.
-
-@node Windows Processes
-@section Subprocesses on Windows 9X/ME and Windows NT/2K
-
- Emacs compiled as a native Windows application (as opposed to the DOS
-version) includes full support for asynchronous subprocesses.
-In the Windows version, synchronous and asynchronous subprocesses work
-fine on both
-Windows 9X and Windows NT/2K as long as you run only 32-bit Windows
-applications. However, when you run a DOS application in a subprocess,
-you may encounter problems or be unable to run the application at all;
-and if you run two DOS applications at the same time in two
-subprocesses, you may have to reboot your system.
-
-Since the standard command interpreter (and most command line utilities)
-on Windows 95 are DOS applications, these problems are significant when
-using that system. But there's nothing we can do about them; only
-Microsoft can fix them.
-
-If you run just one DOS application subprocess, the subprocess should
-work as expected as long as it is ``well-behaved'' and does not perform
-direct screen access or other unusual actions. If you have a CPU
-monitor application, your machine will appear to be 100% busy even when
-the DOS application is idle, but this is only an artifact of the way CPU
-monitors measure processor load.
-
-You must terminate the DOS application before you start any other DOS
-application in a different subprocess. Emacs is unable to interrupt or
-terminate a DOS subprocess. The only way you can terminate such a
-subprocess is by giving it a command that tells its program to exit.
-
-If you attempt to run two DOS applications at the same time in separate
-subprocesses, the second one that is started will be suspended until the
-first one finishes, even if either or both of them are asynchronous.
-
-If you can go to the first subprocess, and tell it to exit, the second
-subprocess should continue normally. However, if the second subprocess
-is synchronous, Emacs itself will be hung until the first subprocess
-finishes. If it will not finish without user input, then you have no
-choice but to reboot if you are running on Windows 9X. If you are
-running on Windows NT/2K, you can use a process viewer application to kill
-the appropriate instance of ntvdm instead (this will terminate both DOS
-subprocesses).
-
-If you have to reboot Windows 9X in this situation, do not use the
-@code{Shutdown} command on the @code{Start} menu; that usually hangs the
-system. Instead, type @kbd{CTL-ALT-@key{DEL}} and then choose
-@code{Shutdown}. That usually works, although it may take a few minutes
-to do its job.
-
-@node Windows System Menu
-@section Using the System Menu on Windows
-
-Emacs compiled as a native Windows application normally turns off the
-Windows feature that tapping the @key{ALT}
-key invokes the Windows menu. The reason is that the @key{ALT} also
-serves as @key{META} in Emacs. When using Emacs, users often press the
-@key{META} key temporarily and then change their minds; if this has the
-effect of bringing up the Windows menu, it alters the meaning of
-subsequent commands. Many users find this frustrating.
-
-@vindex w32-pass-alt-to-system
-You can re-enable Windows' default handling of tapping the @key{ALT} key
-by setting @code{w32-pass-alt-to-system} to a non-@code{nil} value.
-
-@ignore
- arch-tag: f39d2590-5dcc-4318-88d9-0eb73ca10fa2
-@end ignore
+@c This is part of the Emacs manual.
+@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
+@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+@c See file emacs.texi for copying conditions.
+@node Emacs and Microsoft Windows, Manifesto, Mac OS, Top
+@appendix Emacs and Microsoft Windows
+@cindex Microsoft Windows
+
+ This section describes peculiarities of using Emacs on Microsoft
+Windows. Information about Emacs and Microsoft's older MS-DOS
+``operating system'' (also known as ``MS-DOG'') is now in a separate
+manual (@inforef{MS-DOG,, emacs-xtra}).
+
+ Iif you want to use Emacs on Windows, you would normally build Emacs
+specifically for Windows. If you do that, the behavior is reasonably
+similar to what is documented in the rest of the manual, including
+support for long file names, multiple frames, scroll bars, mouse
+menus, and subprocesses. However, a few special considerations apply,
+and they are described here.
+
+@menu
+* Text and Binary:: Text files use CRLF to terminate lines.
+* Windows Processes:: Running subprocesses on Windows.
+* Windows System Menu:: Controlling what the ALT key does.
+@end menu
+
+@node Text and Binary
+@section Text Files and Binary Files
+@cindex text and binary files on MS-DOS/MS-Windows
+
+ GNU Emacs uses newline characters to separate text lines. This is the
+convention used on GNU and Unix.
+
+@cindex end-of-line conversion on MS-DOS/MS-Windows
+ MS-DOS and MS-Windows normally use carriage-return linefeed, a
+two-character sequence, to separate text lines. (Linefeed is the same
+character as newline.) Therefore, convenient editing of typical files
+with Emacs requires conversion of these end-of-line (EOL) sequences.
+And that is what Emacs normally does: it converts carriage-return
+linefeed into newline when reading files, and converts newline into
+carriage-return linefeed when writing files. The same mechanism that
+handles conversion of international character codes does this conversion
+also (@pxref{Coding Systems}).
+
+@cindex cursor location, on MS-DOS
+@cindex point location, on MS-DOS
+ One consequence of this special format-conversion of most files is
+that character positions as reported by Emacs (@pxref{Position Info}) do
+not agree with the file size information known to the operating system.
+
+ In addition, if Emacs recognizes from a file's contents that it uses
+newline rather than carriage-return linefeed as its line separator, it
+does not perform EOL conversion when reading or writing that file.
+Thus, you can read and edit files from GNU and Unix systems on MS-DOS
+with no special effort, and they will retain their Unix-style
+end-of-line convention after you edit them.
+
+ The mode line indicates whether end-of-line translation was used for
+the current buffer. If MS-DOS end-of-line translation is in use for the
+buffer, a backslash @samp{\} is displayed after the coding system
+mnemonic near the beginning of the mode line (@pxref{Mode Line}). If no
+EOL translation was performed, the string @samp{(Unix)} is displayed
+instead of the backslash, to alert you that the file's EOL format is not
+the usual carriage-return linefeed.
+
+@cindex DOS-to-Unix conversion of files
+ To visit a file and specify whether it uses DOS-style or Unix-style
+end-of-line, specify a coding system (@pxref{Text Coding}). For
+example, @kbd{C-x @key{RET} c unix @key{RET} C-x C-f foobar.txt}
+visits the file @file{foobar.txt} without converting the EOLs; if some
+line ends with a carriage-return linefeed pair, Emacs will display
+@samp{^M} at the end of that line. Similarly, you can direct Emacs to
+save a buffer in a specified EOL format with the @kbd{C-x @key{RET} f}
+command. For example, to save a buffer with Unix EOL format, type
+@kbd{C-x @key{RET} f unix @key{RET} C-x C-s}. If you visit a file
+with DOS EOL conversion, then save it with Unix EOL format, that
+effectively converts the file to Unix EOL style, like @code{dos2unix}.
+
+@cindex untranslated file system
+@findex add-untranslated-filesystem
+ When you use NFS or Samba to access file systems that reside on
+computers using GNU or Unix systems, Emacs should not perform
+end-of-line translation on any files in these file systems---not even
+when you create a new file. To request this, designate these file
+systems as @dfn{untranslated} file systems by calling the function
+@code{add-untranslated-filesystem}. It takes one argument: the file
+system name, including a drive letter and optionally a directory. For
+example,
+
+@example
+(add-untranslated-filesystem "Z:")
+@end example
+
+@noindent
+designates drive Z as an untranslated file system, and
+
+@example
+(add-untranslated-filesystem "Z:\\foo")
+@end example
+
+@noindent
+designates directory @file{\foo} on drive Z as an untranslated file
+system.
+
+ Most often you would use @code{add-untranslated-filesystem} in your
+@file{_emacs} file, or in @file{site-start.el} so that all the users at
+your site get the benefit of it.
+
+@findex remove-untranslated-filesystem
+ To countermand the effect of @code{add-untranslated-filesystem}, use
+the function @code{remove-untranslated-filesystem}. This function takes
+one argument, which should be a string just like the one that was used
+previously with @code{add-untranslated-filesystem}.
+
+ Designating a file system as untranslated does not affect character
+set conversion, only end-of-line conversion. Essentially, it directs
+Emacs to create new files with the Unix-style convention of using
+newline at the end of a line. @xref{Coding Systems}.
+
+@vindex file-name-buffer-file-type-alist
+@cindex binary files, on MS-DOS/MS-Windows
+ Some kinds of files should not be converted at all, because their
+contents are not really text. Therefore, Emacs on MS-DOS distinguishes
+certain files as @dfn{binary files}. (This distinction is not part of
+MS-DOS; it is made by Emacs only.) Binary files include executable
+programs, compressed archives, etc. Emacs uses the file name to decide
+whether to treat a file as binary: the variable
+@code{file-name-buffer-file-type-alist} defines the file-name patterns
+that indicate binary files. If a file name matches one of the patterns
+for binary files (those whose associations are of the type
+@code{(@var{pattern} . t)}, Emacs reads and writes that file using the
+@code{no-conversion} coding system (@pxref{Coding Systems}) which turns
+off @emph{all} coding-system conversions, not only the EOL conversion.
+@code{file-name-buffer-file-type-alist} also includes file-name patterns
+for files which are known to be DOS-style text files with
+carriage-return linefeed EOL format, such as @file{CONFIG.SYS}; Emacs
+always writes those files with DOS-style EOLs.
+
+ If a file which belongs to an untranslated file system matches one of
+the file-name patterns in @code{file-name-buffer-file-type-alist}, the
+EOL conversion is determined by @code{file-name-buffer-file-type-alist}.
+
+@node Windows Processes
+@section Subprocesses on Windows 9X/ME and Windows NT/2K
+
+ Emacs compiled as a native Windows application (as opposed to the DOS
+version) includes full support for asynchronous subprocesses.
+In the Windows version, synchronous and asynchronous subprocesses work
+fine on both
+Windows 9X and Windows NT/2K as long as you run only 32-bit Windows
+applications. However, when you run a DOS application in a subprocess,
+you may encounter problems or be unable to run the application at all;
+and if you run two DOS applications at the same time in two
+subprocesses, you may have to reboot your system.
+
+Since the standard command interpreter (and most command line utilities)
+on Windows 95 are DOS applications, these problems are significant when
+using that system. But there's nothing we can do about them; only
+Microsoft can fix them.
+
+If you run just one DOS application subprocess, the subprocess should
+work as expected as long as it is ``well-behaved'' and does not perform
+direct screen access or other unusual actions. If you have a CPU
+monitor application, your machine will appear to be 100% busy even when
+the DOS application is idle, but this is only an artifact of the way CPU
+monitors measure processor load.
+
+You must terminate the DOS application before you start any other DOS
+application in a different subprocess. Emacs is unable to interrupt or
+terminate a DOS subprocess. The only way you can terminate such a
+subprocess is by giving it a command that tells its program to exit.
+
+If you attempt to run two DOS applications at the same time in separate
+subprocesses, the second one that is started will be suspended until the
+first one finishes, even if either or both of them are asynchronous.
+
+If you can go to the first subprocess, and tell it to exit, the second
+subprocess should continue normally. However, if the second subprocess
+is synchronous, Emacs itself will be hung until the first subprocess
+finishes. If it will not finish without user input, then you have no
+choice but to reboot if you are running on Windows 9X. If you are
+running on Windows NT/2K, you can use a process viewer application to kill
+the appropriate instance of ntvdm instead (this will terminate both DOS
+subprocesses).
+
+If you have to reboot Windows 9X in this situation, do not use the
+@code{Shutdown} command on the @code{Start} menu; that usually hangs the
+system. Instead, type @kbd{CTL-ALT-@key{DEL}} and then choose
+@code{Shutdown}. That usually works, although it may take a few minutes
+to do its job.
+
+@node Windows System Menu
+@section Using the System Menu on Windows
+
+Emacs compiled as a native Windows application normally turns off the
+Windows feature that tapping the @key{ALT}
+key invokes the Windows menu. The reason is that the @key{ALT} also
+serves as @key{META} in Emacs. When using Emacs, users often press the
+@key{META} key temporarily and then change their minds; if this has the
+effect of bringing up the Windows menu, it alters the meaning of
+subsequent commands. Many users find this frustrating.
+
+@vindex w32-pass-alt-to-system
+You can re-enable Windows' default handling of tapping the @key{ALT} key
+by setting @code{w32-pass-alt-to-system} to a non-@code{nil} value.
+
+@ignore
+ arch-tag: f39d2590-5dcc-4318-88d9-0eb73ca10fa2
+@end ignore
HCoop / bpt / emacs.git / commitdiff