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ca2565b0 | 1 | @c This is part of the Emacs manual. |
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2 | @c Copyright (C) 1985,86,87,93,94,95,1997,2000,2001 |
3 | @c Free Software Foundation, Inc. | |
ca2565b0 | 4 | @c See file emacs.texi for copying conditions. |
d3d652ca | 5 | @node MS-DOS, Manifesto, Mac OS, Top |
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6 | @appendix Emacs and MS-DOS |
7 | @cindex MS-DOG | |
8 | @cindex MS-DOS peculiarities | |
9 | ||
10 | This section briefly describes the peculiarities of using Emacs under | |
11 | the MS-DOS ``operating system'' (also known as ``MS-DOG''). If you | |
12 | build Emacs for MS-DOS, the binary will also run on Windows 3.X, Windows | |
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13 | NT, Windows 9X/ME, Windows 2000, or OS/2 as a DOS application; the |
14 | information in this chapter applies for all of those systems, if you use | |
15 | an Emacs that was built for MS-DOS. | |
ca2565b0 | 16 | |
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17 | Note that it is possible to build Emacs specifically for Windows NT/2K |
18 | or Windows 9X/ME. If you do that, most of this chapter does not apply; | |
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19 | instead, you get behavior much closer to what is documented in the rest |
20 | of the manual, including support for long file names, multiple frames, | |
21 | scroll bars, mouse menus, and subprocesses. However, the section on | |
22 | text files and binary files does still apply. There are also two | |
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23 | sections at the end of this chapter which apply specifically for the |
24 | Windows version. | |
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25 | |
26 | @menu | |
27 | * Input: MS-DOS Input. Keyboard and mouse usage on MS-DOS. | |
28 | * Display: MS-DOS Display. Fonts, frames and display size on MS-DOS. | |
29 | * Files: MS-DOS File Names. File name conventions on MS-DOS. | |
30 | * Text and Binary:: Text files on MS-DOS use CRLF to separate lines. | |
31 | * Printing: MS-DOS Printing. How to specify the printer on MS-DOS. | |
32 | * I18N: MS-DOS and MULE. Support for internationalization on MS-DOS. | |
33 | * Processes: MS-DOS Processes. Running subprocesses on MS-DOS. | |
34 | * Windows Processes:: Running subprocesses on Windows. | |
35 | * Windows System Menu:: Controlling what the ALT key does. | |
36 | @end menu | |
37 | ||
38 | @node MS-DOS Input | |
39 | @section Keyboard and Mouse on MS-DOS | |
40 | ||
41 | @cindex Meta (under MS-DOS) | |
42 | @cindex Hyper (under MS-DOS) | |
43 | @cindex Super (under MS-DOS) | |
44 | @vindex dos-super-key | |
45 | @vindex dos-hyper-key | |
46 | The PC keyboard maps use the left @key{ALT} key as the @key{META} key. | |
47 | You have two choices for emulating the @key{SUPER} and @key{HYPER} keys: | |
48 | choose either the right @key{CTRL} key or the right @key{ALT} key by | |
49 | setting the variables @code{dos-hyper-key} and @code{dos-super-key} to 1 | |
50 | or 2 respectively. If neither @code{dos-super-key} nor | |
51 | @code{dos-hyper-key} is 1, then by default the right @key{ALT} key is | |
52 | also mapped to the @key{META} key. However, if the MS-DOS international | |
53 | keyboard support program @file{KEYB.COM} is installed, Emacs will | |
54 | @emph{not} map the right @key{ALT} to @key{META}, since it is used for | |
55 | accessing characters like @kbd{~} and @kbd{@@} on non-US keyboard | |
56 | layouts; in this case, you may only use the left @key{ALT} as @key{META} | |
57 | key. | |
58 | ||
59 | @kindex C-j @r{(MS-DOS)} | |
60 | @vindex dos-keypad-mode | |
61 | The variable @code{dos-keypad-mode} is a flag variable that controls | |
62 | what key codes are returned by keys in the numeric keypad. You can also | |
63 | define the keypad @key{ENTER} key to act like @kbd{C-j}, by putting the | |
64 | following line into your @file{_emacs} file: | |
65 | ||
66 | @smallexample | |
ce3203c4 | 67 | ;; @r{Make the @key{ENTER} key from the numeric keypad act as @kbd{C-j}.} |
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68 | (define-key function-key-map [kp-enter] [?\C-j]) |
69 | @end smallexample | |
70 | ||
71 | @kindex DEL @r{(MS-DOS)} | |
72 | @kindex BS @r{(MS-DOS)} | |
73 | The key that is called @key{DEL} in Emacs (because that's how it is | |
74 | designated on most workstations) is known as @key{BS} (backspace) on a | |
75 | PC. That is why the PC-specific terminal initialization remaps the | |
76 | @key{BS} key to act as @key{DEL}; the @key{DEL} key is remapped to act | |
77 | as @kbd{C-d} for the same reasons. | |
78 | ||
79 | @kindex C-g @r{(MS-DOS)} | |
80 | @kindex C-BREAK @r{(MS-DOS)} | |
81 | @cindex quitting on MS-DOS | |
82 | Emacs built for MS-DOS recognizes @kbd{C-@key{BREAK}} as a quit | |
83 | character, just like @kbd{C-g}. This is because Emacs cannot detect | |
84 | that you have typed @kbd{C-g} until it is ready for more input. As a | |
85 | consequence, you cannot use @kbd{C-g} to stop a running command | |
86 | (@pxref{Quitting}). By contrast, @kbd{C-@key{BREAK}} @emph{is} detected | |
87 | as soon as you type it (as @kbd{C-g} is on other systems), so it can be | |
88 | used to stop a running command and for emergency escape | |
89 | (@pxref{Emergency Escape}). | |
90 | ||
91 | @cindex mouse support under MS-DOS | |
92 | Emacs on MS-DOS supports a mouse (on the default terminal only). | |
93 | The mouse commands work as documented, including those that use menus | |
94 | and the menu bar (@pxref{Menu Bar}). Scroll bars don't work in | |
95 | MS-DOS Emacs. PC mice usually have only two buttons; these act as | |
96 | @kbd{Mouse-1} and @kbd{Mouse-2}, but if you press both of them | |
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97 | together, that has the effect of @kbd{Mouse-3}. If the mouse does have |
98 | 3 buttons, Emacs detects that at startup, and all the 3 buttons function | |
99 | normally, as on X. | |
100 | ||
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101 | Help strings for menu-bar and pop-up menus are displayed in the echo |
102 | area when the mouse pointer moves across the menu items. | |
103 | Highlighting of mouse-sensitive text (@pxref{Mouse References}) is also | |
104 | supported. | |
105 | ||
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106 | @cindex mouse, set number of buttons |
107 | @findex msdos-set-mouse-buttons | |
108 | Some versions of mouse drivers don't report the number of mouse | |
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109 | buttons correctly. For example, mice with a wheel report that they |
110 | have 3 buttons, but only 2 of them are passed to Emacs; the clicks on | |
111 | the wheel, which serves as the middle button, are not passed. In | |
112 | these cases, you can use the @kbd{M-x msdos-set-mouse-buttons} command | |
113 | to tell Emacs how many mouse buttons to expect. You could make such a | |
114 | setting permanent by adding this fragment to your @file{_emacs} init | |
115 | file: | |
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116 | |
117 | @example | |
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118 | ;; @r{Treat the mouse like a 2-button mouse.} |
119 | (msdos-set-mouse-buttons 2) | |
b5867e25 | 120 | @end example |
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121 | |
122 | @cindex Windows clipboard support | |
123 | Emacs built for MS-DOS supports clipboard operations when it runs on | |
124 | Windows. Commands that put text on the kill ring, or yank text from the | |
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125 | ring, check the Windows clipboard first, just as Emacs does on the X |
126 | Window System (@pxref{Mouse Commands}). Only the primary selection and | |
127 | the cut buffer are supported by MS-DOS Emacs on Windows; the secondary | |
128 | selection always appears as empty. | |
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129 | |
130 | Due to the way clipboard access is implemented by Windows, the | |
131 | length of text you can put into the clipboard is limited by the amount | |
132 | of free DOS memory that is available to Emacs. Usually, up to 620KB of | |
133 | text can be put into the clipboard, but this limit depends on the system | |
134 | configuration and is lower if you run Emacs as a subprocess of | |
6830ceb7 | 135 | another program. If the killed text does not fit, Emacs outputs a |
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136 | message saying so, and does not put the text into the clipboard. |
137 | ||
138 | Null characters also cannot be put into the Windows clipboard. If the | |
139 | killed text includes null characters, Emacs does not put such text into | |
6830ceb7 | 140 | the clipboard, and displays in the echo area a message to that effect. |
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141 | |
142 | @vindex dos-display-scancodes | |
143 | The variable @code{dos-display-scancodes}, when non-@code{nil}, | |
144 | directs Emacs to display the ASCII value and the keyboard scan code of | |
145 | each keystroke; this feature serves as a complement to the | |
146 | @code{view-lossage} command, for debugging. | |
147 | ||
148 | @node MS-DOS Display | |
149 | @section Display on MS-DOS | |
150 | @cindex faces under MS-DOS | |
151 | @cindex fonts, emulating under MS-DOS | |
152 | ||
153 | Display on MS-DOS cannot use font variants, like bold or italic, | |
154 | but it does support | |
155 | multiple faces, each of which can specify a foreground and a background | |
156 | color. Therefore, you can get the full functionality of Emacs packages | |
157 | that use fonts (such as @code{font-lock}, Enriched Text mode, and | |
158 | others) by defining the relevant faces to use different colors. Use the | |
159 | @code{list-colors-display} command (@pxref{Frame Parameters}) and the | |
160 | @code{list-faces-display} command (@pxref{Faces}) to see what colors and | |
161 | faces are available and what they look like. | |
162 | ||
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163 | @xref{MS-DOS and MULE}, later in this chapter, for information on |
164 | how Emacs displays glyphs and characters that aren't supported by the | |
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165 | native font built into the DOS display. |
166 | ||
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167 | @cindex cursor shape on MS-DOS |
168 | When Emacs starts, it changes the cursor shape to a solid box. This | |
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169 | is for compatibility with other systems, where the box cursor is the |
170 | default in Emacs. This default shape can be changed to a bar by | |
171 | specifying the @code{cursor-type} parameter in the variable | |
172 | @code{default-frame-alist} (@pxref{Creating Frames}). The MS-DOS | |
173 | terminal doesn't support a vertical-bar cursor, so the bar cursor is | |
174 | horizontal, and the @code{@var{width}} parameter, if specified by the | |
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175 | frame parameters, actually determines its height. For this reason, |
176 | the @code{bar} and @code{hbar} cursor types produce the same effect on | |
177 | MS-DOS. As an extension, the bar cursor specification can include the | |
178 | starting scan line of the cursor as well as its width, like this: | |
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179 | |
180 | @example | |
181 | '(cursor-type bar @var{width} . @var{start}) | |
182 | @end example | |
183 | ||
184 | @noindent | |
185 | In addition, if the @var{width} parameter is negative, the cursor bar | |
186 | begins at the top of the character cell. | |
187 | ||
ca2565b0 | 188 | @cindex frames on MS-DOS |
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189 | The MS-DOS terminal can only display a single frame at a time. The |
190 | Emacs frame facilities work on MS-DOS much as they do on text-only | |
191 | terminals (@pxref{Frames}). When you run Emacs from a DOS window on | |
192 | MS-Windows, you can make the visible frame smaller than the full | |
193 | screen, but Emacs still cannot display more than a single frame at a | |
194 | time. | |
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195 | |
196 | @cindex frame size under MS-DOS | |
197 | @findex mode4350 | |
198 | @findex mode25 | |
199 | The @code{mode4350} command switches the display to 43 or 50 | |
200 | lines, depending on your hardware; the @code{mode25} command switches | |
201 | to the default 80x25 screen size. | |
202 | ||
203 | By default, Emacs only knows how to set screen sizes of 80 columns by | |
204 | 25, 28, 35, 40, 43 or 50 rows. However, if your video adapter has | |
205 | special video modes that will switch the display to other sizes, you can | |
206 | have Emacs support those too. When you ask Emacs to switch the frame to | |
207 | @var{n} rows by @var{m} columns dimensions, it checks if there is a | |
208 | variable called @code{screen-dimensions-@var{n}x@var{m}}, and if so, | |
209 | uses its value (which must be an integer) as the video mode to switch | |
210 | to. (Emacs switches to that video mode by calling the BIOS @code{Set | |
211 | Video Mode} function with the value of | |
212 | @code{screen-dimensions-@var{n}x@var{m}} in the @code{AL} register.) | |
213 | For example, suppose your adapter will switch to 66x80 dimensions when | |
214 | put into video mode 85. Then you can make Emacs support this screen | |
215 | size by putting the following into your @file{_emacs} file: | |
216 | ||
217 | @example | |
218 | (setq screen-dimensions-66x80 85) | |
219 | @end example | |
220 | ||
221 | Since Emacs on MS-DOS can only set the frame size to specific | |
222 | supported dimensions, it cannot honor every possible frame resizing | |
223 | request. When an unsupported size is requested, Emacs chooses the next | |
224 | larger supported size beyond the specified size. For example, if you | |
225 | ask for 36x80 frame, you will get 40x80 instead. | |
226 | ||
227 | The variables @code{screen-dimensions-@var{n}x@var{m}} are used only | |
228 | when they exactly match the specified size; the search for the next | |
229 | larger supported size ignores them. In the above example, even if your | |
230 | VGA supports 38x80 dimensions and you define a variable | |
231 | @code{screen-dimensions-38x80} with a suitable value, you will still get | |
232 | 40x80 screen when you ask for a 36x80 frame. If you want to get the | |
233 | 38x80 size in this case, you can do it by setting the variable named | |
234 | @code{screen-dimensions-36x80} with the same video mode value as | |
235 | @code{screen-dimensions-38x80}. | |
236 | ||
237 | Changing frame dimensions on MS-DOS has the effect of changing all the | |
238 | other frames to the new dimensions. | |
239 | ||
240 | @node MS-DOS File Names | |
241 | @section File Names on MS-DOS | |
242 | @cindex file names under MS-DOS | |
243 | @cindex init file, default name under MS-DOS | |
244 | ||
245 | MS-DOS normally uses a backslash, @samp{\}, to separate name units | |
246 | within a file name, instead of the slash used on other systems. Emacs | |
247 | on MS-DOS permits use of either slash or backslash, and also knows | |
248 | about drive letters in file names. | |
249 | ||
250 | On MS-DOS, file names are case-insensitive and limited to eight | |
251 | characters, plus optionally a period and three more characters. Emacs | |
252 | knows enough about these limitations to handle file names that were | |
253 | meant for other operating systems. For instance, leading dots @samp{.} | |
254 | in file names are invalid in MS-DOS, so Emacs transparently converts | |
255 | them to underscores @samp{_}; thus your default init file (@pxref{Init | |
256 | File}) is called @file{_emacs} on MS-DOS. Excess characters before or | |
257 | after the period are generally ignored by MS-DOS itself; thus, if you | |
258 | visit the file @file{LongFileName.EvenLongerExtension}, you will | |
259 | silently get @file{longfile.eve}, but Emacs will still display the long | |
260 | file name on the mode line. Other than that, it's up to you to specify | |
261 | file names which are valid under MS-DOS; the transparent conversion as | |
262 | described above only works on file names built into Emacs. | |
263 | ||
264 | @cindex backup file names on MS-DOS | |
265 | The above restrictions on the file names on MS-DOS make it almost | |
266 | impossible to construct the name of a backup file (@pxref{Backup | |
267 | Names}) without losing some of the original file name characters. For | |
268 | example, the name of a backup file for @file{docs.txt} is | |
269 | @file{docs.tx~} even if single backup is used. | |
270 | ||
271 | @cindex file names under Windows 95/NT | |
272 | @cindex long file names in DOS box under Windows 95/NT | |
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273 | If you run Emacs as a DOS application under Windows 9X, Windows ME, or |
274 | Windows 2000, you can turn on support for long file names. If you do | |
275 | that, Emacs doesn't truncate file names or convert them to lower case; | |
276 | instead, it uses the file names that you specify, verbatim. To enable | |
277 | long file name support, set the environment variable @env{LFN} to | |
278 | @samp{y} before starting Emacs. Unfortunately, Windows NT doesn't allow | |
279 | DOS programs to access long file names, so Emacs built for MS-DOS will | |
280 | only see their short 8+3 aliases. | |
ca2565b0 | 281 | |
60a96371 | 282 | @cindex @env{HOME} directory under MS-DOS |
ca2565b0 | 283 | MS-DOS has no notion of home directory, so Emacs on MS-DOS pretends |
60a96371 | 284 | that the directory where it is installed is the value of @env{HOME} |
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285 | environment variable. That is, if your Emacs binary, |
286 | @file{emacs.exe}, is in the directory @file{c:/utils/emacs/bin}, then | |
60a96371 | 287 | Emacs acts as if @env{HOME} were set to @samp{c:/utils/emacs}. In |
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288 | particular, that is where Emacs looks for the init file @file{_emacs}. |
289 | With this in mind, you can use @samp{~} in file names as an alias for | |
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290 | the home directory, as you would on GNU or Unix. You can also set |
291 | @env{HOME} variable in the environment before starting Emacs; its | |
292 | value will then override the above default behavior. | |
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293 | |
294 | Emacs on MS-DOS handles the directory name @file{/dev} specially, | |
295 | because of a feature in the emulator libraries of DJGPP that pretends | |
296 | I/O devices have names in that directory. We recommend that you avoid | |
297 | using an actual directory named @file{/dev} on any disk. | |
298 | ||
299 | @node Text and Binary | |
300 | @section Text Files and Binary Files | |
301 | @cindex text and binary files on MS-DOS/MS-Windows | |
302 | ||
303 | GNU Emacs uses newline characters to separate text lines. This is the | |
8e375db2 | 304 | convention used on GNU and Unix. |
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305 | |
306 | @cindex end-of-line conversion on MS-DOS/MS-Windows | |
307 | MS-DOS and MS-Windows normally use carriage-return linefeed, a | |
308 | two-character sequence, to separate text lines. (Linefeed is the same | |
309 | character as newline.) Therefore, convenient editing of typical files | |
310 | with Emacs requires conversion of these end-of-line (EOL) sequences. | |
311 | And that is what Emacs normally does: it converts carriage-return | |
312 | linefeed into newline when reading files, and converts newline into | |
313 | carriage-return linefeed when writing files. The same mechanism that | |
314 | handles conversion of international character codes does this conversion | |
315 | also (@pxref{Coding Systems}). | |
316 | ||
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317 | @cindex cursor location, on MS-DOS |
318 | @cindex point location, on MS-DOS | |
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319 | One consequence of this special format-conversion of most files is |
320 | that character positions as reported by Emacs (@pxref{Position Info}) do | |
321 | not agree with the file size information known to the operating system. | |
322 | ||
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323 | In addition, if Emacs recognizes from a file's contents that it uses |
324 | newline rather than carriage-return linefeed as its line separator, it | |
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325 | does not perform EOL conversion when reading or writing that file. |
326 | Thus, you can read and edit files from GNU and Unix systems on MS-DOS | |
327 | with no special effort, and they will retain their Unix-style | |
328 | end-of-line convention after you edit them. | |
ca2565b0 | 329 | |
ca2565b0 | 330 | The mode line indicates whether end-of-line translation was used for |
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331 | the current buffer. If MS-DOS end-of-line translation is in use for the |
332 | buffer, a backslash @samp{\} is displayed after the coding system | |
333 | mnemonic near the beginning of the mode line (@pxref{Mode Line}). If no | |
334 | EOL translation was performed, the string @samp{(Unix)} is displayed | |
335 | instead of the backslash, to alert you that the file's EOL format is not | |
336 | the usual carriage-return linefeed. | |
337 | ||
338 | @cindex DOS-to-Unix conversion of files | |
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339 | To visit a file and specify whether it uses DOS-style or Unix-style |
340 | end-of-line, specify a coding system (@pxref{Specify Coding}). For | |
341 | example, @kbd{C-x @key{RET} c unix @key{RET} C-x C-f foobar.txt} | |
342 | visits the file @file{foobar.txt} without converting the EOLs; if some | |
343 | line ends with a carriage-return linefeed pair, Emacs will display | |
344 | @samp{^M} at the end of that line. Similarly, you can direct Emacs to | |
345 | save a buffer in a specified EOL format with the @kbd{C-x @key{RET} f} | |
346 | command. For example, to save a buffer with Unix EOL format, type | |
347 | @kbd{C-x @key{RET} f unix @key{RET} C-x C-s}. If you visit a file | |
348 | with DOS EOL conversion, then save it with Unix EOL format, that | |
349 | effectively converts the file to Unix EOL style, like @code{dos2unix}. | |
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350 | |
351 | @cindex untranslated file system | |
352 | @findex add-untranslated-filesystem | |
353 | When you use NFS or Samba to access file systems that reside on | |
8e375db2 | 354 | computers using GNU or Unix systems, Emacs should not perform |
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355 | end-of-line translation on any files in these file systems--not even |
356 | when you create a new file. To request this, designate these file | |
357 | systems as @dfn{untranslated} file systems by calling the function | |
358 | @code{add-untranslated-filesystem}. It takes one argument: the file | |
359 | system name, including a drive letter and optionally a directory. For | |
360 | example, | |
361 | ||
362 | @example | |
363 | (add-untranslated-filesystem "Z:") | |
364 | @end example | |
365 | ||
366 | @noindent | |
367 | designates drive Z as an untranslated file system, and | |
368 | ||
369 | @example | |
370 | (add-untranslated-filesystem "Z:\\foo") | |
371 | @end example | |
372 | ||
373 | @noindent | |
374 | designates directory @file{\foo} on drive Z as an untranslated file | |
375 | system. | |
376 | ||
377 | Most often you would use @code{add-untranslated-filesystem} in your | |
378 | @file{_emacs} file, or in @file{site-start.el} so that all the users at | |
379 | your site get the benefit of it. | |
380 | ||
381 | @findex remove-untranslated-filesystem | |
382 | To countermand the effect of @code{add-untranslated-filesystem}, use | |
383 | the function @code{remove-untranslated-filesystem}. This function takes | |
384 | one argument, which should be a string just like the one that was used | |
385 | previously with @code{add-untranslated-filesystem}. | |
386 | ||
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387 | Designating a file system as untranslated does not affect character |
388 | set conversion, only end-of-line conversion. Essentially, it directs | |
389 | Emacs to create new files with the Unix-style convention of using | |
390 | newline at the end of a line. @xref{Coding Systems}. | |
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391 | |
392 | @vindex file-name-buffer-file-type-alist | |
393 | @cindex binary files, on MS-DOS/MS-Windows | |
394 | Some kinds of files should not be converted at all, because their | |
395 | contents are not really text. Therefore, Emacs on MS-DOS distinguishes | |
396 | certain files as @dfn{binary files}. (This distinction is not part of | |
397 | MS-DOS; it is made by Emacs only.) Binary files include executable | |
398 | programs, compressed archives, etc. Emacs uses the file name to decide | |
399 | whether to treat a file as binary: the variable | |
400 | @code{file-name-buffer-file-type-alist} defines the file-name patterns | |
401 | that indicate binary files. If a file name matches one of the patterns | |
402 | for binary files (those whose associations are of the type | |
403 | @code{(@var{pattern} . t)}, Emacs reads and writes that file using the | |
404 | @code{no-conversion} coding system (@pxref{Coding Systems}) which turns | |
405 | off @emph{all} coding-system conversions, not only the EOL conversion. | |
406 | @code{file-name-buffer-file-type-alist} also includes file-name patterns | |
407 | for files which are known to be DOS-style text files with | |
408 | carriage-return linefeed EOL format, such as @file{CONFIG.SYS}; Emacs | |
409 | always writes those files with DOS-style EOLs. | |
410 | ||
411 | If a file which belongs to an untranslated file system matches one of | |
412 | the file-name patterns in @code{file-name-buffer-file-type-alist}, the | |
413 | EOL conversion is determined by @code{file-name-buffer-file-type-alist}. | |
414 | ||
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415 | @node MS-DOS Printing |
416 | @section Printing and MS-DOS | |
417 | ||
418 | Printing commands, such as @code{lpr-buffer} (@pxref{Hardcopy}) and | |
e7f961bc | 419 | @code{ps-print-buffer} (@pxref{PostScript}) can work in MS-DOS and |
9d9d68ed | 420 | MS-Windows by sending the output to one of the printer ports, if a |
892c6176 | 421 | Posix-style @code{lpr} program is unavailable. The same Emacs |
8e375db2 RS |
422 | variables control printing on all systems (@pxref{Hardcopy}), but in |
423 | some cases they have different default values on MS-DOS and | |
424 | MS-Windows. | |
9d9d68ed | 425 | |
7ada9313 | 426 | @vindex printer-name @r{(MS-DOS)} |
ca2565b0 | 427 | If you want to use your local printer, printing on it in the usual DOS |
9d9d68ed AI |
428 | manner, then set the Lisp variable @code{lpr-command} to @code{""} (its |
429 | default value) and @code{printer-name} to the name of the printer | |
430 | port---for example, @code{"PRN"}, the usual local printer port (that's | |
431 | the default), or @code{"LPT2"}, or @code{"COM1"} for a serial printer. | |
432 | You can also set @code{printer-name} to a file name, in which case | |
433 | ``printed'' output is actually appended to that file. If you set | |
434 | @code{printer-name} to @code{"NUL"}, printed output is silently | |
ca2565b0 AI |
435 | discarded (sent to the system null device). |
436 | ||
9d9d68ed AI |
437 | On MS-Windows, when the Windows network software is installed, you can |
438 | also use a printer shared by another machine by setting | |
439 | @code{printer-name} to the UNC share name for that printer--for example, | |
440 | @code{"//joes_pc/hp4si"}. (It doesn't matter whether you use forward | |
441 | slashes or backslashes here.) To find out the names of shared printers, | |
442 | run the command @samp{net view} at a DOS command prompt to obtain a list | |
5f6fbc5f | 443 | of servers, and @samp{net view @var{server-name}} to see the names of printers |
f82e36c6 EZ |
444 | (and directories) shared by that server. Alternatively, click the |
445 | @samp{Network Neighborhood} icon on your desktop, and look for machines | |
446 | which share their printers via the network. | |
447 | ||
0034a96c EZ |
448 | @cindex @samp{net use}, and printing on MS-Windows |
449 | @cindex networked printers (MS-Windows) | |
450 | If the printer doesn't appear in the output of @samp{net view}, or | |
451 | if setting @code{printer-name} to the UNC share name doesn't produce a | |
452 | hardcopy on that printer, you can use the @samp{net use} command to | |
453 | connect a local print port such as @code{"LPT2"} to the networked | |
454 | printer. For example, typing @kbd{net use LPT2: | |
455 | \\joes_pc\hp4si}@footnote{ | |
456 | Note that the @samp{net use} command requires the UNC share name to be | |
457 | typed with the Windows-style backslashes, while the value of | |
458 | @code{printer-name} can be set with either forward- or backslashes.} | |
459 | causes Windows to @dfn{capture} the LPT2 port and redirect the printed | |
460 | material to the printer connected to the machine @code{joes_pc}. | |
461 | After this command, setting @code{printer-name} to @code{"LPT2"} | |
1deddb56 | 462 | should produce the hardcopy on the networked printer. |
0034a96c | 463 | |
cb54d522 | 464 | With some varieties of Windows network software, you can instruct |
3ae8380b | 465 | Windows to capture a specific printer port such as @code{"LPT2"}, and |
cb54d522 EZ |
466 | redirect it to a networked printer via the @w{@code{Control |
467 | Panel->Printers}} applet instead of @samp{net use}. | |
468 | ||
f82e36c6 EZ |
469 | Some printers expect DOS codepage encoding of non-ASCII text, even |
470 | though they are connected to a Windows machine which uses a different | |
471 | encoding for the same locale. For example, in the Latin-1 locale, DOS | |
472 | uses codepage 850 whereas Windows uses codepage 1252. @xref{MS-DOS and | |
473 | MULE}. When you print to such printers from Windows, you can use the | |
474 | @kbd{C-x RET c} (@code{universal-coding-system-argument}) command before | |
475 | @kbd{M-x lpr-buffer}; Emacs will then convert the text to the DOS | |
476 | codepage that you specify. For example, @kbd{C-x RET c cp850-dos RET | |
477 | M-x lpr-region RET} will print the region while converting it to the | |
478 | codepage 850 encoding. You may need to create the @code{cp@var{nnn}} | |
479 | coding system with @kbd{M-x codepage-setup}. | |
9d9d68ed AI |
480 | |
481 | If you set @code{printer-name} to a file name, it's best to use an | |
ca2565b0 AI |
482 | absolute file name. Emacs changes the working directory according to |
483 | the default directory of the current buffer, so if the file name in | |
9d9d68ed AI |
484 | @code{printer-name} is relative, you will end up with several such |
485 | files, each one in the directory of the buffer from which the printing | |
486 | was done. | |
ca2565b0 AI |
487 | |
488 | @findex print-buffer @r{(MS-DOS)} | |
489 | @findex print-region @r{(MS-DOS)} | |
490 | @vindex lpr-headers-switches @r{(MS-DOS)} | |
491 | The commands @code{print-buffer} and @code{print-region} call the | |
492 | @code{pr} program, or use special switches to the @code{lpr} program, to | |
9d9d68ed AI |
493 | produce headers on each printed page. MS-DOS and MS-Windows don't |
494 | normally have these programs, so by default, the variable | |
495 | @code{lpr-headers-switches} is set so that the requests to print page | |
496 | headers are silently ignored. Thus, @code{print-buffer} and | |
497 | @code{print-region} produce the same output as @code{lpr-buffer} and | |
498 | @code{lpr-region}, respectively. If you do have a suitable @code{pr} | |
499 | program (for example, from GNU Textutils), set | |
500 | @code{lpr-headers-switches} to @code{nil}; Emacs will then call | |
ca2565b0 | 501 | @code{pr} to produce the page headers, and print the resulting output as |
9d9d68ed | 502 | specified by @code{printer-name}. |
ca2565b0 AI |
503 | |
504 | @vindex print-region-function @r{(MS-DOS)} | |
505 | @cindex lpr usage under MS-DOS | |
506 | @vindex lpr-command @r{(MS-DOS)} | |
507 | @vindex lpr-switches @r{(MS-DOS)} | |
9d9d68ed AI |
508 | Finally, if you do have an @code{lpr} work-alike, you can set the |
509 | variable @code{lpr-command} to @code{"lpr"}. Then Emacs will use | |
510 | @code{lpr} for printing, as on other systems. (If the name of the | |
511 | program isn't @code{lpr}, set @code{lpr-command} to specify where to | |
512 | find it.) The variable @code{lpr-switches} has its standard meaning | |
513 | when @code{lpr-command} is not @code{""}. If the variable | |
514 | @code{printer-name} has a string value, it is used as the value for the | |
515 | @code{-P} option to @code{lpr}, as on Unix. | |
ca2565b0 AI |
516 | |
517 | @findex ps-print-buffer @r{(MS-DOS)} | |
518 | @findex ps-spool-buffer @r{(MS-DOS)} | |
4251fcec | 519 | @vindex ps-printer-name @r{(MS-DOS)} |
ca2565b0 AI |
520 | @vindex ps-lpr-command @r{(MS-DOS)} |
521 | @vindex ps-lpr-switches @r{(MS-DOS)} | |
9d9d68ed | 522 | A parallel set of variables, @code{ps-lpr-command}, |
e7f961bc | 523 | @code{ps-lpr-switches}, and @code{ps-printer-name} (@pxref{PostScript |
5d66c9e1 | 524 | Variables}), defines how PostScript files should be printed. These |
9d9d68ed AI |
525 | variables are used in the same way as the corresponding variables |
526 | described above for non-PostScript printing. Thus, the value of | |
527 | @code{ps-printer-name} is used as the name of the device (or file) to | |
528 | which PostScript output is sent, just as @code{printer-name} is used for | |
529 | non-PostScript printing. (There are two distinct sets of variables in | |
530 | case you have two printers attached to two different ports, and only one | |
531 | of them is a PostScript printer.) | |
532 | ||
533 | The default value of the variable @code{ps-lpr-command} is @code{""}, | |
534 | which causes PostScript output to be sent to the printer port specified | |
535 | by @code{ps-printer-name}, but @code{ps-lpr-command} can also be set to | |
536 | the name of a program which will accept PostScript files. Thus, if you | |
537 | have a non-PostScript printer, you can set this variable to the name of | |
538 | a PostScript interpreter program (such as Ghostscript). Any switches | |
539 | that need to be passed to the interpreter program are specified using | |
540 | @code{ps-lpr-switches}. (If the value of @code{ps-printer-name} is a | |
541 | string, it will be added to the list of switches as the value for the | |
542 | @code{-P} option. This is probably only useful if you are using | |
543 | @code{lpr}, so when using an interpreter typically you would set | |
544 | @code{ps-printer-name} to something other than a string so it is | |
545 | ignored.) | |
ca2565b0 AI |
546 | |
547 | For example, to use Ghostscript for printing on an Epson printer | |
4251fcec | 548 | connected to the @samp{LPT2} port, put this in your @file{_emacs} file: |
ca2565b0 AI |
549 | |
550 | @example | |
9d9d68ed | 551 | (setq ps-printer-name t) ; Ghostscript doesn't understand -P |
ca2565b0 AI |
552 | (setq ps-lpr-command "c:/gs/gs386") |
553 | (setq ps-lpr-switches '("-q" "-dNOPAUSE" | |
554 | "-sDEVICE=epson" | |
555 | "-r240x72" | |
556 | "-sOutputFile=LPT2" | |
9d9d68ed | 557 | "-Ic:/gs")) |
ca2565b0 AI |
558 | @end example |
559 | ||
560 | @noindent | |
561 | (This assumes that Ghostscript is installed in the @file{"c:/gs"} | |
562 | directory.) | |
563 | ||
9d9d68ed AI |
564 | @vindex dos-printer |
565 | @vindex dos-ps-printer | |
566 | For backwards compatibility, the value of @code{dos-printer} | |
567 | (@code{dos-ps-printer}), if it has a value, overrides the value of | |
568 | @code{printer-name} (@code{ps-printer-name}), on MS-DOS and MS-Windows | |
569 | only. | |
570 | ||
571 | ||
ca2565b0 AI |
572 | @node MS-DOS and MULE |
573 | @section International Support on MS-DOS | |
574 | @cindex international support @r{(MS-DOS)} | |
575 | ||
576 | Emacs on MS-DOS supports the same international character sets as it | |
892c6176 | 577 | does on GNU, Unix and other platforms (@pxref{International}), including |
ca2565b0 | 578 | coding systems for converting between the different character sets. |
892c6176 RS |
579 | However, due to incompatibilities between MS-DOS/MS-Windows and other systems, |
580 | there are several DOS-specific aspects of this support that you should | |
ca2565b0 AI |
581 | be aware of. This section describes these aspects. |
582 | ||
583 | @table @kbd | |
584 | @item M-x dos-codepage-setup | |
585 | Set up Emacs display and coding systems as appropriate for the current | |
586 | DOS codepage. | |
587 | ||
588 | @item M-x codepage-setup | |
589 | Create a coding system for a certain DOS codepage. | |
590 | @end table | |
591 | ||
592 | @cindex codepage, MS-DOS | |
593 | @cindex DOS codepages | |
594 | MS-DOS is designed to support one character set of 256 characters at | |
595 | any given time, but gives you a variety of character sets to choose | |
596 | from. The alternative character sets are known as @dfn{DOS codepages}. | |
597 | Each codepage includes all 128 ASCII characters, but the other 128 | |
598 | characters (codes 128 through 255) vary from one codepage to another. | |
599 | Each DOS codepage is identified by a 3-digit number, such as 850, 862, | |
600 | etc. | |
601 | ||
97878c08 | 602 | In contrast to X, which lets you use several fonts at the same time, |
cf47c5b2 EZ |
603 | MS-DOS normally doesn't allow use of several codepages in a single |
604 | session. MS-DOS was designed to load a single codepage at system | |
605 | startup, and require you to reboot in order to change | |
606 | it@footnote{Normally, one particular codepage is burnt into the display | |
607 | memory, while other codepages can be installed by modifying system | |
608 | configuration files, such as @file{CONFIG.SYS}, and rebooting. While | |
609 | third-party software is known to exist that allows to change the | |
610 | codepage without rebooting, we describe here how a stock MS-DOS system | |
611 | behaves.}. Much the same limitation applies when you run DOS | |
ca2565b0 AI |
612 | executables on other systems such as MS-Windows. |
613 | ||
614 | @cindex unibyte operation @r{(MS-DOS)} | |
615 | If you invoke Emacs on MS-DOS with the @samp{--unibyte} option | |
616 | (@pxref{Initial Options}), Emacs does not perform any conversion of | |
617 | non-ASCII characters. Instead, it reads and writes any non-ASCII | |
618 | characters verbatim, and sends their 8-bit codes to the display | |
619 | verbatim. Thus, unibyte Emacs on MS-DOS supports the current codepage, | |
620 | whatever it may be, but cannot even represent any other characters. | |
621 | ||
622 | @vindex dos-codepage | |
623 | For multibyte operation on MS-DOS, Emacs needs to know which | |
624 | characters the chosen DOS codepage can display. So it queries the | |
625 | system shortly after startup to get the chosen codepage number, and | |
626 | stores the number in the variable @code{dos-codepage}. Some systems | |
627 | return the default value 437 for the current codepage, even though the | |
628 | actual codepage is different. (This typically happens when you use the | |
629 | codepage built into the display hardware.) You can specify a different | |
630 | codepage for Emacs to use by setting the variable @code{dos-codepage} in | |
631 | your init file. | |
632 | ||
633 | @cindex language environment, automatic selection on @r{MS-DOS} | |
48870849 | 634 | Multibyte Emacs supports only certain DOS codepages: those which can |
36e20969 EZ |
635 | display Far-Eastern scripts, like the Japanese codepage 932, and those |
636 | that encode a single ISO 8859 character set. | |
637 | ||
638 | The Far-Eastern codepages can directly display one of the MULE | |
639 | character sets for these countries, so Emacs simply sets up to use the | |
640 | appropriate terminal coding system that is supported by the codepage. | |
641 | The special features described in the rest of this section mostly | |
642 | pertain to codepages that encode ISO 8859 character sets. | |
643 | ||
644 | For the codepages which correspond to one of the ISO character sets, | |
48870849 EZ |
645 | Emacs knows the character set name based on the codepage number. Emacs |
646 | automatically creates a coding system to support reading and writing | |
647 | files that use the current codepage, and uses this coding system by | |
648 | default. The name of this coding system is @code{cp@var{nnn}}, where | |
649 | @var{nnn} is the codepage number.@footnote{The standard Emacs coding | |
650 | systems for ISO 8859 are not quite right for the purpose, because | |
651 | typically the DOS codepage does not match the standard ISO character | |
652 | codes. For example, the letter @samp{@,{c}} (@samp{c} with cedilla) has | |
653 | code 231 in the standard Latin-1 character set, but the corresponding | |
654 | DOS codepage 850 uses code 135 for this glyph.} | |
ca2565b0 AI |
655 | |
656 | @cindex mode line @r{(MS-DOS)} | |
657 | All the @code{cp@var{nnn}} coding systems use the letter @samp{D} (for | |
658 | ``DOS'') as their mode-line mnemonic. Since both the terminal coding | |
659 | system and the default coding system for file I/O are set to the proper | |
660 | @code{cp@var{nnn}} coding system at startup, it is normal for the mode | |
661 | line on MS-DOS to begin with @samp{-DD\-}. @xref{Mode Line}. | |
36e20969 | 662 | Far-Eastern DOS terminals do not use the @code{cp@var{nnn}} coding |
892c6176 | 663 | systems, and thus their initial mode line looks like the Emacs default. |
ca2565b0 AI |
664 | |
665 | Since the codepage number also indicates which script you are using, | |
666 | Emacs automatically runs @code{set-language-environment} to select the | |
667 | language environment for that script (@pxref{Language Environments}). | |
668 | ||
669 | If a buffer contains a character belonging to some other ISO 8859 | |
670 | character set, not the one that the chosen DOS codepage supports, Emacs | |
671 | displays it using a sequence of ASCII characters. For example, if the | |
672 | current codepage doesn't have a glyph for the letter @samp{@`o} (small | |
673 | @samp{o} with a grave accent), it is displayed as @samp{@{`o@}}, where | |
674 | the braces serve as a visual indication that this is a single character. | |
675 | (This may look awkward for some non-Latin characters, such as those from | |
676 | Greek or Hebrew alphabets, but it is still readable by a person who | |
677 | knows the language.) Even though the character may occupy several | |
678 | columns on the screen, it is really still just a single character, and | |
679 | all Emacs commands treat it as one. | |
680 | ||
e18c8fa8 EZ |
681 | @cindex IBM graphics characters (MS-DOS) |
682 | @cindex box-drawing characters (MS-DOS) | |
683 | @cindex line-drawing characters (MS-DOS) | |
ca2565b0 AI |
684 | Not all characters in DOS codepages correspond to ISO 8859 |
685 | characters---some are used for other purposes, such as box-drawing | |
e18c8fa8 EZ |
686 | characters and other graphics. Emacs maps these characters to two |
687 | special character sets called @code{eight-bit-control} and | |
688 | @code{eight-bit-graphic}, and displays them as their IBM glyphs. | |
689 | However, you should be aware that other systems might display these | |
690 | characters differently, so you should avoid them in text that might be | |
691 | copied to a different operating system, or even to another DOS machine | |
692 | that uses a different codepage. | |
ca2565b0 | 693 | |
e18c8fa8 | 694 | @vindex dos-unsupported-character-glyph |
ca2565b0 AI |
695 | Emacs supports many other characters sets aside from ISO 8859, but it |
696 | cannot display them on MS-DOS. So if one of these multibyte characters | |
01f767b7 EZ |
697 | appears in a buffer, Emacs on MS-DOS displays them as specified by the |
698 | @code{dos-unsupported-character-glyph} variable; by default, this glyph | |
699 | is an empty triangle. Use the @kbd{C-u C-x =} command to display the | |
700 | actual code and character set of such characters. @xref{Position Info}. | |
ca2565b0 AI |
701 | |
702 | @findex codepage-setup | |
703 | By default, Emacs defines a coding system to support the current | |
704 | codepage. To define a coding system for some other codepage (e.g., to | |
705 | visit a file written on a DOS machine in another country), use the | |
706 | @kbd{M-x codepage-setup} command. It prompts for the 3-digit code of | |
707 | the codepage, with completion, then creates the coding system for the | |
708 | specified codepage. You can then use the new coding system to read and | |
709 | write files, but you must specify it explicitly for the file command | |
710 | when you want to use it (@pxref{Specify Coding}). | |
711 | ||
712 | These coding systems are also useful for visiting a file encoded using | |
713 | a DOS codepage, using Emacs running on some other operating system. | |
714 | ||
f82e36c6 | 715 | @cindex MS-Windows codepages |
8e375db2 | 716 | MS-Windows provides its own codepages, which are different from the |
f82e36c6 EZ |
717 | DOS codepages for the same locale. For example, DOS codepage 850 |
718 | supports the same character set as Windows codepage 1252; DOS codepage | |
719 | 855 supports the same character set as Windows codepage 1251, etc. | |
720 | The MS-Windows version of Emacs uses the current codepage for display | |
721 | when invoked with the @samp{-nw} option. | |
722 | ||
ca2565b0 AI |
723 | @node MS-DOS Processes |
724 | @section Subprocesses on MS-DOS | |
725 | ||
726 | @cindex compilation under MS-DOS | |
727 | @cindex inferior processes under MS-DOS | |
728 | @findex compile @r{(MS-DOS)} | |
729 | @findex grep @r{(MS-DOS)} | |
730 | Because MS-DOS is a single-process ``operating system,'' | |
731 | asynchronous subprocesses are not available. In particular, Shell | |
732 | mode and its variants do not work. Most Emacs features that use | |
733 | asynchronous subprocesses also don't work on MS-DOS, including | |
f0787adc | 734 | Shell mode and GUD. When in doubt, try and see; commands that |
6830ceb7 | 735 | don't work output an error message saying that asynchronous processes |
ca2565b0 AI |
736 | aren't supported. |
737 | ||
738 | Compilation under Emacs with @kbd{M-x compile}, searching files with | |
739 | @kbd{M-x grep} and displaying differences between files with @kbd{M-x | |
740 | diff} do work, by running the inferior processes synchronously. This | |
741 | means you cannot do any more editing until the inferior process | |
742 | finishes. | |
743 | ||
f0787adc EZ |
744 | Spell checking also works, by means of special support for synchronous |
745 | invocation of the @code{ispell} program. This is slower than the | |
892c6176 | 746 | asynchronous invocation on other platforms |
f0787adc EZ |
747 | |
748 | Instead of the Shell mode, which doesn't work on MS-DOS, you can use | |
749 | the @kbd{M-x eshell} command. This invokes the Eshell package that | |
892c6176 | 750 | implements a Posix-like shell entirely in Emacs Lisp. |
f0787adc | 751 | |
ca2565b0 AI |
752 | By contrast, Emacs compiled as native Windows application |
753 | @strong{does} support asynchronous subprocesses. @xref{Windows | |
754 | Processes}. | |
755 | ||
756 | @cindex printing under MS-DOS | |
757 | Printing commands, such as @code{lpr-buffer} (@pxref{Hardcopy}) and | |
e7f961bc | 758 | @code{ps-print-buffer} (@pxref{PostScript}), work in MS-DOS by sending |
ca2565b0 AI |
759 | the output to one of the printer ports. @xref{MS-DOS Printing}. |
760 | ||
761 | When you run a subprocess synchronously on MS-DOS, make sure the | |
762 | program terminates and does not try to read keyboard input. If the | |
763 | program does not terminate on its own, you will be unable to terminate | |
764 | it, because MS-DOS provides no general way to terminate a process. | |
765 | Pressing @kbd{C-c} or @kbd{C-@key{BREAK}} might sometimes help in these | |
766 | cases. | |
767 | ||
768 | Accessing files on other machines is not supported on MS-DOS. Other | |
769 | network-oriented commands such as sending mail, Web browsing, remote | |
770 | login, etc., don't work either, unless network access is built into | |
771 | MS-DOS with some network redirector. | |
772 | ||
773 | @cindex directory listing on MS-DOS | |
774 | @vindex dired-listing-switches @r{(MS-DOS)} | |
775 | Dired on MS-DOS uses the @code{ls-lisp} package where other | |
776 | platforms use the system @code{ls} command. Therefore, Dired on | |
777 | MS-DOS supports only some of the possible options you can mention in | |
778 | the @code{dired-listing-switches} variable. The options that work are | |
779 | @samp{-A}, @samp{-a}, @samp{-c}, @samp{-i}, @samp{-r}, @samp{-S}, | |
780 | @samp{-s}, @samp{-t}, and @samp{-u}. | |
781 | ||
782 | @node Windows Processes | |
ff43a665 | 783 | @section Subprocesses on Windows 9X/ME and Windows NT/2K |
ca2565b0 AI |
784 | |
785 | Emacs compiled as a native Windows application (as opposed to the DOS | |
786 | version) includes full support for asynchronous subprocesses. | |
787 | In the Windows version, synchronous and asynchronous subprocesses work | |
788 | fine on both | |
ff43a665 | 789 | Windows 9X and Windows NT/2K as long as you run only 32-bit Windows |
ca2565b0 AI |
790 | applications. However, when you run a DOS application in a subprocess, |
791 | you may encounter problems or be unable to run the application at all; | |
792 | and if you run two DOS applications at the same time in two | |
793 | subprocesses, you may have to reboot your system. | |
794 | ||
795 | Since the standard command interpreter (and most command line utilities) | |
796 | on Windows 95 are DOS applications, these problems are significant when | |
797 | using that system. But there's nothing we can do about them; only | |
798 | Microsoft can fix them. | |
799 | ||
800 | If you run just one DOS application subprocess, the subprocess should | |
801 | work as expected as long as it is ``well-behaved'' and does not perform | |
802 | direct screen access or other unusual actions. If you have a CPU | |
803 | monitor application, your machine will appear to be 100% busy even when | |
804 | the DOS application is idle, but this is only an artifact of the way CPU | |
805 | monitors measure processor load. | |
806 | ||
807 | You must terminate the DOS application before you start any other DOS | |
808 | application in a different subprocess. Emacs is unable to interrupt or | |
809 | terminate a DOS subprocess. The only way you can terminate such a | |
810 | subprocess is by giving it a command that tells its program to exit. | |
811 | ||
812 | If you attempt to run two DOS applications at the same time in separate | |
813 | subprocesses, the second one that is started will be suspended until the | |
814 | first one finishes, even if either or both of them are asynchronous. | |
815 | ||
816 | If you can go to the first subprocess, and tell it to exit, the second | |
817 | subprocess should continue normally. However, if the second subprocess | |
818 | is synchronous, Emacs itself will be hung until the first subprocess | |
819 | finishes. If it will not finish without user input, then you have no | |
ff43a665 EZ |
820 | choice but to reboot if you are running on Windows 9X. If you are |
821 | running on Windows NT/2K, you can use a process viewer application to kill | |
ca2565b0 AI |
822 | the appropriate instance of ntvdm instead (this will terminate both DOS |
823 | subprocesses). | |
824 | ||
ff43a665 | 825 | If you have to reboot Windows 9X in this situation, do not use the |
ca2565b0 AI |
826 | @code{Shutdown} command on the @code{Start} menu; that usually hangs the |
827 | system. Instead, type @kbd{CTL-ALT-@key{DEL}} and then choose | |
828 | @code{Shutdown}. That usually works, although it may take a few minutes | |
829 | to do its job. | |
830 | ||
831 | @node Windows System Menu | |
832 | @section Using the System Menu on Windows | |
833 | ||
834 | Emacs compiled as a native Windows application normally turns off the | |
835 | Windows feature that tapping the @key{ALT} | |
836 | key invokes the Windows menu. The reason is that the @key{ALT} also | |
837 | serves as @key{META} in Emacs. When using Emacs, users often press the | |
838 | @key{META} key temporarily and then change their minds; if this has the | |
839 | effect of bringing up the Windows menu, it alters the meaning of | |
840 | subsequent commands. Many users find this frustrating. | |
841 | ||
842 | @vindex w32-pass-alt-to-system | |
843 | You can reenable Windows's default handling of tapping the @key{ALT} key | |
844 | by setting @code{w32-pass-alt-to-system} to a non-@code{nil} value. | |
845 |