@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 86, 87, 93, 94, 95, 1997 Free Software Foundation, Inc.
+@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, Antinews, Top
-@appendix Emacs and MS-DOS
-@cindex MS-DOG
-@cindex MS-DOS peculiarities
-
- This section briefly describes the peculiarities of using Emacs under
-the MS-DOS ``operating system'' (also known as ``MS-DOG''). If you
-build Emacs for MS-DOS, the binary will also run on Windows 3.X, Windows
-NT, Windows 9X, or OS/2 as a DOS application; the information in this
-chapter applies for all of those systems, if you use an Emacs that was
-built for MS-DOS.
-
- Note that it is possible to build Emacs specifically for Windows NT or
-Windows 9X. 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 Windows
-NT and 9X.
+@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
-* Input: MS-DOS Input. Keyboard and mouse usage 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.
+* 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 MS-DOS Input
-@section Keyboard and Mouse on MS-DOS
-
-@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
-;; Make the Enter key from the Numeric keypad act as C-j.
-(define-key function-key-map [kp-enter] [?\C-j])
-@end smallexample
-
-@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{DEL} 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 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}.
-
-@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 X Windows
-(@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 prints 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 prints 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 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.
-
- The section @ref{MS-DOS and MULE}, later in this chapter, describes
-how Emacs displays glyphs and characters which aren't supported by the
-native font built into the DOS display.
-
-@cindex frames on MS-DOS
- Multiple frames (@pxref{Frames}) are supported on MS-DOS, but they all
-overlap, so you only see a single frame at any given moment. That
-single visible frame occupies the entire screen. When you run Emacs
-from MS-Windows DOS box, 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, 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 @code{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 @code{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 @code{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 @code{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 in Unix. You can also set @code{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 Unix, on which GNU Emacs was developed, and on GNU
-systems since they are modeled on Unix.
+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
handles conversion of international character codes does this conversion
also (@pxref{Coding Systems}).
-@cindex cursor location, under MS-DOS
-@cindex point location, under MS-DOS
+@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.
-@vindex file-name-buffer-file-type-alist
- Some kinds of files should not be converted, because their contents
-are not really text. Therefore, Emacs on MS-DOS distinguishes certain
-files as @dfn{binary files}, and reads and writes them verbatim. (This
-distinction is not part of MS-DOS; it is made by Emacs only.) These
-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. Note that if a file name matches one of the
-patterns for binary files in @code{file-name-buffer-file-type-alist},
-Emacs uses the @code{no-conversion} coding system (@pxref{Coding
-Systems}) which turns off @emph{all} coding-system conversions, not only
-the EOL conversion.
-
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 conversion when reading or writing that file. Thus,
-you can read and edit files from Unix or GNU systems on MS-DOS with no
-special effort, and they will be left with their Unix-style EOLs.
-
-@findex find-file-text
-@findex find-file-binary
- You can visit a file and specify whether to treat a file as text or
-binary using the commands @code{find-file-text} and
-@code{find-file-binary}. End-of-line conversion is part of the general
-coding system conversion mechanism, so another way to control whether to
-treat a file as text or binary is with the commands for specifying a
-coding system (@pxref{Specify Coding}). For example,
-@kbd{C-x @key{RET} c undecided-unix @key{RET} C-x C-f foobar.txt}
-visits the file @file{foobar.txt} without converting the EOLs.
+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. Normally a colon appears after the coding system
-letter near the beginning of the mode line. If MS-DOS end-of-line
-translation is in use for the buffer, this character changes to a
-backslash.
+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 Unix or GNU systems, Emacs should not perform
-end-of-line translation on any files in these file systems--not even
+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
one argument, which should be a string just like the one that was used
previously with @code{add-untranslated-filesystem}.
-@node MS-DOS Printing
-@section Printing and MS-DOS
-
- Printing commands, such as @code{lpr-buffer} (@pxref{Hardcopy}) 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
-Unix-style @code{lpr} program is unavailable. This behaviour is
-controlled by the same variables that control printing with @code{lpr}
-on Unix (@pxref{Hardcopy}, @pxref{Postscript Variables}), but the
-defaults for these variables on MS-DOS and MS-Windows are not the same
-as the defaults on Unix.
-
-@vindex printer-name
- 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 server-name} to see the names of printers
-(and directories) shared by that server.
-
- 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
-@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 @samp{LPT2} port, put this on 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
+ 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}.
-@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 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 Unix,
-there are several DOS-specific aspects of this support that users should
-be aware of. This section describes these aspects.
-
-@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 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 Windows, which lets you use several fonts at the same
-time, MS-DOS doesn't allow use of several codepages in a single session.
-Instead, MS-DOS loads a single codepage at system startup, and you must
-reboot MS-DOS 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.}. 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-ASCII characters. Instead, it reads and writes any non-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 that encode
-a single ISO 8859 character set, and it knows which ISO character set
-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}.
-
- 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 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.
-
-@vindex dos-unsupported-character-glyph
- 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 cannot represent these characters
-internally, so when you read a file that uses these characters, they are
-converted into a particular character code, specified by the variable
-@code{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{Specify Coding}).
-
- These coding systems are also useful for visiting a file encoded using
-a DOS codepage, using Emacs running on some other operating system.
-
-@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
-spelling correction and GUD. When in doubt, try and see; commands that
-don't work print 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.
-
- By contrast, Emacs compiled as native Windows application
-@strong{does} support asynchronous subprocesses. @xref{Windows
-Processes}.
-
-@cindex printing under MS-DOS
- Printing commands, such as @code{lpr-buffer} (@pxref{Hardcopy}) 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}.
+@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 95 and NT
+@section Subprocesses on Windows 9X/ME and Windows NT/2K
-Emacs compiled as a native Windows application (as opposed to the DOS
+ 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 95 and Windows NT as long as you run only 32-bit Windows
+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
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 95. If you are
-running on Windows NT, you can use a process viewer application to kill
+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 95 in this situation, do not use the
+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
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.
+subsequent commands. Many users find this frustrating.
@vindex w32-pass-alt-to-system
-You can reenable Windows's default handling of tapping the @key{ALT} key
+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