@menu
* Introduction:: What documentation belongs here?
+@iftex
+* Picture Mode:: Editing pictures made up of characters using
+ the quarter-plane screen model.
+
* Autorevert:: Auto Reverting non-file buffers.
* Subdir Switches:: Subdirectory switches in Dired.
* Advanced Calendar/Diary Usage:: Advanced Calendar/Diary customization.
* Emerge:: A convenient way of merging two versions of a program.
-* Picture Mode:: Editing pictures made up of characters using
- the quarter-plane screen model.
-
* Advanced VC Usage:: Advanced VC (version control) features.
* Fortran:: Fortran mode and its special features.
-* MS-DOS:: Using Emacs on MS-DOS (otherwise known as "MS-DOG").
+* MS-DOS:: Using Emacs on MS-DOS (otherwise known as @dfn{MS-DOG}).
+@end iftex
* Index::
@end menu
@unnumbered Introduction
This manual contains detailed information about various features that
-are too specialized to be included in the Emacs manual. It is
+are too specialized to be included in the printed Emacs manual. It is
intended to be readable by anyone having a basic knowledge of Emacs.
However, certain sections may be intended for a more specialized
audience, such as Elisp authors. This should be clearly pointed out
at the beginning of these sections.
-This manual is intended as a complement, rather than an alternative,
-to other ways to gain a more detailed knowledge of Emacs than the
-Emacs manual can provide, such as browsing packages using @kbd{C-h p},
-accessing mode documentation using @kbd{C-h m} and browsing user
-options using Custom. Also, certain packages, or collections of
-related features, have their own manuals. The present manual is
-mainly intended to be a collection of smaller specialized features,
-too small to get their own manual.
+Certain packages, or collections of related features, have their own
+manuals, separate from the main Emacs User's manual. This manual is
+intended as a complement, rather than an alternative, to reading those
+additional manuals; in a nutshell, it is a collection of smaller
+specialized features, too small or too obscure to justify their own
+manual.
Sections intended specifically for Elisp programmers can follow the
style of the Elisp manual. Other sections should follow the style of
the Emacs manual.
-@node Autorevert
-@chapter Auto Reverting non-file Buffers
-
-Normally Global Auto Revert Mode only reverts file buffers. There are
-two ways to auto-revert certain non-file buffers: enabling Auto Revert
-Mode in those buffers (using @kbd{M-x auto-revert-mode}) and setting
-@code{global-auto-revert-non-file-buffers} to @code{t}. The latter
-enables Auto Reverting for all types of buffers for which it is
-implemented, that is, for the types of buffers listed in the menu
-below.
-
-Like file buffers, non-file buffers should normally not revert while
-you are working on them, or while they contain information that might
-get lost after reverting. Therefore, they do not revert if they are
-``modified''. This can get tricky, because deciding when a non-file
-buffer should be marked modified is usually more difficult than for
-file buffers.
-
-Another tricky detail is that, for efficiency reasons, Auto Revert
-often does not try to detect all possible changes in the buffer, only
-changes that are ``major'' or easy to detect. Hence, enabling
-auto-reverting for a non-file buffer does not always guarantee that
-all information in the buffer is up to date and does not necessarily
-make manual reverts useless.
-
-At the other extreme, certain buffers automatically auto-revert every
-@code{auto-revert-interval} seconds. (This currently only applies to
-the Buffer Menu.) In this case, Auto Revert does not print any
-messages while reverting, even when @code{auto-revert-verbose} is
-non-@code{nil}.
-
-The details depend on the particular types of buffers and are
-explained in the corresponding sections.
-
-@menu
-* Auto Reverting the Buffer Menu::
-* Auto Reverting Dired::
-* Supporting additional buffers::
-@end menu
-
-@node Auto Reverting the Buffer Menu
-@section Auto Reverting the Buffer Menu
-
-If auto-reverting of non-file buffers is enabled, the Buffer Menu
-automatically reverts every @code{auto-revert-interval} seconds,
-whether there is a need for it or not. (It would probably take longer
-to check whether there is a need than to actually revert.)
-
-If the Buffer Menu inappropriately gets marked modified, just revert
-it manually using @kbd{g} and auto-reverting will resume. However, if
-you marked certain buffers to get deleted or to be displayed, you have
-to be careful, because reverting erases all marks. The fact that
-adding marks sets the buffer's modified flag prevents Auto Revert from
-automatically erasing the marks.
-
-@node Auto Reverting Dired
-@section Auto Reverting Dired buffers
-
-Auto-reverting Dired buffers currently works on GNU or Unix style
-operating systems. It may not work satisfactorily on some other
-systems.
-
-Dired buffers only auto-revert when the file list of the buffer's main
-directory changes. They do not auto-revert when information about a
-particular file changes or when inserted subdirectories change. To be
-sure that @emph{all} listed information is up to date, you have to
-manually revert using @kbd{g}, @emph{even} if auto-reverting is
-enabled in the Dired buffer. Sometimes, you might get the impression
-that modifying or saving files listed in the main directory actually
-does cause auto-reverting. This is because making changes to a file,
-or saving it, very often causes changes in the directory itself, for
-instance, through backup files or auto-save files. However, this is
-not guaranteed.
-
-If the Dired buffer is marked modified and there are no changes you
-want to protect, then most of the time you can make auto-reverting
-resume by manually reverting the buffer using @kbd{g}. There is one
-exception. If you flag or mark files, you can safely revert the
-buffer. This will not erase the flags or marks (unless the marked
-file has been deleted, of course). However, the buffer will stay
-modified, even after reverting, and auto-reverting will not resume.
-This is because, if you flag or mark files, you may be working on the
-buffer and you might not want the buffer to change without warning.
-If you want auto-reverting to resume in the presence of marks and
-flags, mark the buffer non-modified using @kbd{M-~}. However, adding,
-deleting or changing marks or flags will mark it modified again.
-
-Remote Dired buffers are not auto-reverted. Neither are Dired buffers
-for which you used shell wildcards or file arguments to list only some
-of the files. @samp{*Find*} and @samp{*Locate*} buffers do not
-auto-revert either.
-
-@node Supporting additional buffers
-@section Adding Support for Auto-Reverting additional Buffers.
-
-This section is intended for Elisp programmers who would like to add
-support for auto-reverting new types of buffers.
-
-To support auto-reverting the buffer must first of all have a
-@code{revert-buffer-function}. @xref{Definition of
-revert-buffer-function,, Reverting, elisp, the Emacs Lisp Reference Manual}.
-
-In addition, it @emph{must} have a @code{buffer-stale-function}.
-
-@defvar buffer-stale-function
-The value of this variable is a function to check whether a non-file
-buffer needs reverting. This should be a function with one optional
-argument @var{noconfirm}. The function should return non-@code{nil}
-if the buffer should be reverted. The buffer is current when this
-function is called.
-
-While this function is mainly intended for use in auto-reverting, it
-could be used for other purposes as well. For instance, if
-auto-reverting is not enabled, it could be used to warn the user that
-the buffer needs reverting. The idea behind the @var{noconfirm}
-argument is that it should be @code{t} if the buffer is going to be
-reverted without asking the user and @code{nil} if the function is
-just going to be used to warn the user that the buffer is out of date.
-In particular, for use in auto-reverting, @var{noconfirm} is @code{t}.
-If the function is only going to be used for auto-reverting, you can
-ignore the @var{noconfirm} argument.
-
-If you just want to automatically auto-revert every
-@code{auto-revert-interval} seconds, use:
-
-@example
-(set (make-local-variable 'buffer-stale-function)
- #'(lambda (&optional noconfirm) 'fast))
-@end example
-
-@noindent
-in the buffer's mode function.
-
-The special return value @samp{fast} tells the caller that the need
-for reverting was not checked, but that reverting the buffer is fast.
-It also tells Auto Revert not to print any revert messages, even if
-@code{auto-revert-verbose} is non-@code{nil}. This is important, as
-getting revert messages every @code{auto-revert-interval} seconds can
-be very annoying. The information provided by this return value could
-also be useful if the function is consulted for purposes other than
-auto-reverting.
-@end defvar
-
-Once the buffer has a @code{revert-buffer-function} and a
-@code{buffer-stale-function}, several problems usually remain.
-
-The buffer will only auto-revert if it is marked unmodified. Hence,
-you will have to make sure that various functions mark the buffer
-modified if and only if either the buffer contains information that
-might be lost by reverting or there is reason to believe that the user
-might be inconvenienced by auto-reverting, because he is actively
-working on the buffer. The user can always override this by manually
-adjusting the modified status of the buffer. To support this, calling
-the @code{revert-buffer-function} on a buffer that is marked
-unmodified should always keep the buffer marked unmodified.
-
-It is important to assure that point does not continuously jump around
-as a consequence of auto-reverting. Of course, moving point might be
-inevitable if the buffer radically changes.
-
-You should make sure that the @code{revert-buffer-function} does not
-print messages that unnecessarily duplicate Auto Revert's own messages
-if @code{auto-revert-verbose} is @code{t} and effectively override a
-@code{nil} value for @code{auto-revert-verbose}. Hence, adapting a
-mode for auto-reverting often involves getting rid of such messages.
-This is especially important for buffers that automatically
-auto-revert every @code{auto-revert-interval} seconds.
-
-Also, you may want to update the documentation string of
-@code{global-auto-revert-non-file-buffers}.
-
-@ifinfo
-Finally, you should add a node to this chapter's menu. This node
-@end ifinfo
-@ifnotinfo
-Finally, you should add a section to this chapter. This section
-@end ifnotinfo
-should at the very least make clear whether enabling auto-reverting
-for the buffer reliably assures that all information in the buffer is
-completely up to date (or will be after @code{auto-revert-interval}
-seconds).
-
-@node Subdir Switches
-@chapter Subdirectory Switches in Dired
-
-You can insert subdirectories with specified @code{ls} switches in
-Dired buffers, using @kbd{C-u i}. You can change the @code{ls}
-switches of an already inserted subdirectory using @kbd{C-u l}.
-
-In Emacs versions 22.1 and later, Dired remembers the switches, so
-that reverting the buffer will not change them back to the main
-directory's switches. Deleting a subdirectory forgets about its
-switches.
-
-Using @code{dired-undo} (usually bound to @kbd{C-_} and @kbd{C-x u})
-to reinsert or delete subdirectories, that were inserted with explicit
-switches, can bypass Dired's machinery for remembering (or forgetting)
-switches. Deleting a subdirectory using @code{dired-undo} does not
-forget its switches. When later reinserted using @kbd{i}, it will be
-reinserted using its old switches. Using @code{dired-undo} to
-reinsert a subdirectory that was deleted using the regular
-Dired commands (not @code{dired-undo}) will originally insert it with
-its old switches. However, reverting the buffer will relist it using
-the buffer's default switches. If any of this yields problems, you
-can easily correct the situation using @kbd{C-u i} or @kbd{C-u l}.
-
-Dired does not remember the @code{R} switch. Inserting a subdirectory
-with switches that include the @code{R} switch is equivalent with
-inserting each of its subdirectories using all remaining switches.
-For instance, updating or killing a subdirectory that was inserted
-with the @code{R} switch will not update or kill its subdirectories.
-
-The buffer's default switches do not affect subdirectories that were
-inserted using explicitly specified switches. In particular,
-commands such as @kbd{s}, that change the buffer's switches do not
-affect such subdirectories. (They do affect subdirectories without
-explicitly assigned switches, however.)
-
-You can make Dired forget about all subdirectory switches and relist
-all subdirectories with the buffer's default switches using
-@kbd{M-x dired-reset-subdir-switches}. This also reverts the Dired buffer.
-
-
-@c Moved here from the Emacs Lisp Reference Manual, 2005-03-26.
-@node Advanced Calendar/Diary Usage
-@chapter Customizing the Calendar and Diary
-
- There are many customizations that you can use to make the calendar and
-diary suit your personal tastes.
-
-@menu
-* Calendar Customizing:: Defaults you can set.
-* Holiday Customizing:: Defining your own holidays.
-* Date Display Format:: Changing the format.
-* Time Display Format:: Changing the format.
-* Daylight Savings:: Changing the default.
-* Diary Customizing:: Defaults you can set.
-* Hebrew/Islamic Entries:: How to obtain them.
-* Fancy Diary Display:: Enhancing the diary display, sorting entries,
- using included diary files.
-* Sexp Diary Entries:: Fancy things you can do.
-@end menu
-
-@node Calendar Customizing
-@section Customizing the Calendar
-@vindex calendar-holiday-marker
-@vindex diary-entry-marker
- The variable @code{calendar-holiday-marker} specifies how to mark a
-date as being a holiday. Its value may be a single-character string
-to insert next to the date, or a face name to use for displaying the
-date. Likewise, the variable @code{diary-entry-marker} specifies how
-to mark a date that has diary entries. The calendar creates faces
-named @code{holiday-face} and @code{diary-face} for these purposes;
-those symbols are the default values of these variables.
-
-@vindex calendar-load-hook
- The variable @code{calendar-load-hook} is a normal hook run when the
-calendar package is first loaded (before actually starting to display
-the calendar).
-
-@vindex initial-calendar-window-hook
- Starting the calendar runs the normal hook
-@code{initial-calendar-window-hook}. Recomputation of the calendar
-display does not run this hook. But if you leave the calendar with the
-@kbd{q} command and reenter it, the hook runs again.@refill
-
-@vindex today-visible-calendar-hook
- The variable @code{today-visible-calendar-hook} is a normal hook run
-after the calendar buffer has been prepared with the calendar when the
-current date is visible in the window. One use of this hook is to
-replace today's date with asterisks; to do that, use the hook function
-@code{calendar-star-date}.
-
-@findex calendar-star-date
-@example
-(add-hook 'today-visible-calendar-hook 'calendar-star-date)
-@end example
-
-@noindent
-Another standard hook function marks the current date, either by
-changing its face or by adding an asterisk. Here's how to use it:
-
-@findex calendar-mark-today
-@example
-(add-hook 'today-visible-calendar-hook 'calendar-mark-today)
-@end example
-
-@noindent
-@vindex calendar-today-marker
-The variable @code{calendar-today-marker} specifies how to mark
-today's date. Its value should be a single-character string to insert
-next to the date or a face name to use for displaying the date. A
-face named @code{calendar-today-face} is provided for this purpose;
-that symbol is the default for this variable.
-
-@vindex today-invisible-calendar-hook
-@noindent
- A similar normal hook, @code{today-invisible-calendar-hook} is run if
-the current date is @emph{not} visible in the window.
-
-@vindex calendar-move-hook
- Each of the calendar cursor motion commands runs the hook
-@code{calendar-move-hook} after it moves the cursor.
-
-@node Holiday Customizing
-@section Customizing the Holidays
-
-@vindex calendar-holidays
-@vindex christian-holidays
-@vindex hebrew-holidays
-@vindex islamic-holidays
- Emacs knows about holidays defined by entries on one of several lists.
-You can customize these lists of holidays to your own needs, adding or
-deleting holidays. The lists of holidays that Emacs uses are for
-general holidays (@code{general-holidays}), local holidays
-(@code{local-holidays}), Christian holidays (@code{christian-holidays}),
-Hebrew (Jewish) holidays (@code{hebrew-holidays}), Islamic (Muslim)
-holidays (@code{islamic-holidays}), and other holidays
-(@code{other-holidays}).
-
-@vindex general-holidays
- The general holidays are, by default, holidays common throughout the
-United States. To eliminate these holidays, set @code{general-holidays}
-to @code{nil}.
-
-@vindex local-holidays
- There are no default local holidays (but sites may supply some). You
-can set the variable @code{local-holidays} to any list of holidays, as
-described below.
-
-@vindex all-christian-calendar-holidays
-@vindex all-hebrew-calendar-holidays
-@vindex all-islamic-calendar-holidays
- By default, Emacs does not include all the holidays of the religions
-that it knows, only those commonly found in secular calendars. For a
-more extensive collection of religious holidays, you can set any (or
-all) of the variables @code{all-christian-calendar-holidays},
-@code{all-hebrew-calendar-holidays}, or
-@code{all-islamic-calendar-holidays} to @code{t}. If you want to
-eliminate the religious holidays, set any or all of the corresponding
-variables @code{christian-holidays}, @code{hebrew-holidays}, and
-@code{islamic-holidays} to @code{nil}.@refill
-
-@vindex other-holidays
- You can set the variable @code{other-holidays} to any list of
-holidays. This list, normally empty, is intended for individual use.
-
-@cindex holiday forms
- Each of the lists (@code{general-holidays}, @code{local-holidays},
-@code{christian-holidays}, @code{hebrew-holidays},
-@code{islamic-holidays}, and @code{other-holidays}) is a list of
-@dfn{holiday forms}, each holiday form describing a holiday (or
-sometimes a list of holidays).
-
- Here is a table of the possible kinds of holiday form. Day numbers
-and month numbers count starting from 1, but ``dayname'' numbers
-count Sunday as 0. The element @var{string} is always the
-name of the holiday, as a string.
-
-@table @code
-@item (holiday-fixed @var{month} @var{day} @var{string})
-A fixed date on the Gregorian calendar.
-
-@item (holiday-float @var{month} @var{dayname} @var{k} @var{string})
-The @var{k}th @var{dayname} in @var{month} on the Gregorian calendar
-(@var{dayname}=0 for Sunday, and so on); negative @var{k} means count back
-from the end of the month.
-
-@item (holiday-hebrew @var{month} @var{day} @var{string})
-A fixed date on the Hebrew calendar.
-
-@item (holiday-islamic @var{month} @var{day} @var{string})
-A fixed date on the Islamic calendar.
-
-@item (holiday-julian @var{month} @var{day} @var{string})
-A fixed date on the Julian calendar.
-
-@item (holiday-sexp @var{sexp} @var{string})
-A date calculated by the Lisp expression @var{sexp}. The expression
-should use the variable @code{year} to compute and return the date of a
-holiday, or @code{nil} if the holiday doesn't happen this year. The
-value of @var{sexp} must represent the date as a list of the form
-@code{(@var{month} @var{day} @var{year})}.
-
-@item (if @var{condition} @var{holiday-form})
-A holiday that happens only if @var{condition} is true.
-
-@item (@var{function} @r{[}@var{args}@r{]})
-A list of dates calculated by the function @var{function}, called with
-arguments @var{args}.
-@end table
-
- For example, suppose you want to add Bastille Day, celebrated in
-France on July 14. You can do this as follows:
-
-@smallexample
-(setq other-holidays '((holiday-fixed 7 14 "Bastille Day")))
-@end smallexample
-
-@noindent
-The holiday form @code{(holiday-fixed 7 14 "Bastille Day")} specifies the
-fourteenth day of the seventh month (July).
-
- Many holidays occur on a specific day of the week, at a specific time
-of month. Here is a holiday form describing Hurricane Supplication Day,
-celebrated in the Virgin Islands on the fourth Monday in August:
-
-@smallexample
-(holiday-float 8 1 4 "Hurricane Supplication Day")
-@end smallexample
-
-@noindent
-Here the 8 specifies August, the 1 specifies Monday (Sunday is 0,
-Tuesday is 2, and so on), and the 4 specifies the fourth occurrence in
-the month (1 specifies the first occurrence, 2 the second occurrence,
-@minus{}1 the last occurrence, @minus{}2 the second-to-last occurrence, and
-so on).
-
- You can specify holidays that occur on fixed days of the Hebrew,
-Islamic, and Julian calendars too. For example,
-
-@smallexample
-(setq other-holidays
- '((holiday-hebrew 10 2 "Last day of Hanukkah")
- (holiday-islamic 3 12 "Mohammed's Birthday")
- (holiday-julian 4 2 "Jefferson's Birthday")))
-@end smallexample
-
-@noindent
-adds the last day of Hanukkah (since the Hebrew months are numbered with
-1 starting from Nisan), the Islamic feast celebrating Mohammed's
-birthday (since the Islamic months are numbered from 1 starting with
-Muharram), and Thomas Jefferson's birthday, which is 2 April 1743 on the
-Julian calendar.
-
- To include a holiday conditionally, use either Emacs Lisp's @code{if} or the
-@code{holiday-sexp} form. For example, American presidential elections
-occur on the first Tuesday after the first Monday in November of years
-divisible by 4:
-
-@smallexample
-(holiday-sexp '(if (= 0 (% year 4))
- (calendar-gregorian-from-absolute
- (1+ (calendar-dayname-on-or-before
- 1 (+ 6 (calendar-absolute-from-gregorian
- (list 11 1 year)))))))
- "US Presidential Election")
-@end smallexample
-
-@noindent
-or
-
-@smallexample
-(if (= 0 (% displayed-year 4))
- (fixed 11
- (extract-calendar-day
- (calendar-gregorian-from-absolute
- (1+ (calendar-dayname-on-or-before
- 1 (+ 6 (calendar-absolute-from-gregorian
- (list 11 1 displayed-year)))))))
- "US Presidential Election"))
-@end smallexample
-
- Some holidays just don't fit into any of these forms because special
-calculations are involved in their determination. In such cases you
-must write a Lisp function to do the calculation. To include eclipses,
-for example, add @code{(eclipses)} to @code{other-holidays}
-and write an Emacs Lisp function @code{eclipses} that returns a
-(possibly empty) list of the relevant Gregorian dates among the range
-visible in the calendar window, with descriptive strings, like this:
-
-@smallexample
-(((6 27 1991) "Lunar Eclipse") ((7 11 1991) "Solar Eclipse") ... )
-@end smallexample
-
-@node Date Display Format
-@section Date Display Format
-@vindex calendar-date-display-form
-
- You can customize the manner of displaying dates in the diary, in mode
-lines, and in messages by setting @code{calendar-date-display-form}.
-This variable holds a list of expressions that can involve the variables
-@code{month}, @code{day}, and @code{year}, which are all numbers in
-string form, and @code{monthname} and @code{dayname}, which are both
-alphabetic strings. In the American style, the default value of this
-list is as follows:
-
-@smallexample
-((if dayname (concat dayname ", ")) monthname " " day ", " year)
-@end smallexample
-
-@noindent
-while in the European style this value is the default:
-
-@smallexample
-((if dayname (concat dayname ", ")) day " " monthname " " year)
-@end smallexample
-
-@noindent
-The ISO standard date representation is this:
-
-@smallexample
-(year "-" month "-" day)
-@end smallexample
-
-@noindent
-This specifies a typical American format:
-
-@smallexample
-(month "/" day "/" (substring year -2))
-@end smallexample
-
-@node Time Display Format
-@section Time Display Format
-@vindex calendar-time-display-form
-
- The calendar and diary by default display times of day in the
-conventional American style with the hours from 1 through 12, minutes,
-and either @samp{am} or @samp{pm}. If you prefer the European style,
-also known in the US as military, in which the hours go from 00 to 23,
-you can alter the variable @code{calendar-time-display-form}. This
-variable is a list of expressions that can involve the variables
-@code{12-hours}, @code{24-hours}, and @code{minutes}, which are all
-numbers in string form, and @code{am-pm} and @code{time-zone}, which are
-both alphabetic strings. The default value of
-@code{calendar-time-display-form} is as follows:
-
-@smallexample
-(12-hours ":" minutes am-pm
- (if time-zone " (") time-zone (if time-zone ")"))
-@end smallexample
-
-@noindent
-Here is a value that provides European style times:
-
-@smallexample
-(24-hours ":" minutes
- (if time-zone " (") time-zone (if time-zone ")"))
-@end smallexample
-
-@node Daylight Savings
-@section Daylight Savings Time
-@cindex daylight savings time
-
- Emacs understands the difference between standard time and daylight
-savings time---the times given for sunrise, sunset, solstices,
-equinoxes, and the phases of the moon take that into account. The rules
-for daylight savings time vary from place to place and have also varied
-historically from year to year. To do the job properly, Emacs needs to
-know which rules to use.
-
- Some operating systems keep track of the rules that apply to the place
-where you are; on these systems, Emacs gets the information it needs
-from the system automatically. If some or all of this information is
-missing, Emacs fills in the gaps with the rules currently used in
-Cambridge, Massachusetts, which is the center of GNU's world.
-
-
-@vindex calendar-daylight-savings-starts
-@vindex calendar-daylight-savings-ends
- If the default choice of rules is not appropriate for your location,
-you can tell Emacs the rules to use by setting the variables
-@code{calendar-daylight-savings-starts} and
-@code{calendar-daylight-savings-ends}. Their values should be Lisp
-expressions that refer to the variable @code{year}, and evaluate to the
-Gregorian date on which daylight savings time starts or (respectively)
-ends, in the form of a list @code{(@var{month} @var{day} @var{year})}.
-The values should be @code{nil} if your area does not use daylight
-savings time.
-
- Emacs uses these expressions to determine the start and end dates of
-daylight savings time as holidays and for correcting times of day in the
-solar and lunar calculations.
-
- The values for Cambridge, Massachusetts are as follows:
-
-@example
-@group
-(calendar-nth-named-day 1 0 4 year)
-(calendar-nth-named-day -1 0 10 year)
-@end group
-@end example
-
-@noindent
-i.e., the first 0th day (Sunday) of the fourth month (April) in
-the year specified by @code{year}, and the last Sunday of the tenth month
-(October) of that year. If daylight savings time were
-changed to start on October 1, you would set
-@code{calendar-daylight-savings-starts} to this:
-
-@example
-(list 10 1 year)
-@end example
-
- For a more complex example, suppose daylight savings time begins on
-the first of Nisan on the Hebrew calendar. You should set
-@code{calendar-daylight-savings-starts} to this value:
-
-@example
-(calendar-gregorian-from-absolute
- (calendar-absolute-from-hebrew
- (list 1 1 (+ year 3760))))
-@end example
-
-@noindent
-because Nisan is the first month in the Hebrew calendar and the Hebrew
-year differs from the Gregorian year by 3760 at Nisan.
-
- If there is no daylight savings time at your location, or if you want
-all times in standard time, set @code{calendar-daylight-savings-starts}
-and @code{calendar-daylight-savings-ends} to @code{nil}.
-
-@vindex calendar-daylight-time-offset
- The variable @code{calendar-daylight-time-offset} specifies the
-difference between daylight savings time and standard time, measured in
-minutes. The value for Cambridge is 60.
-
-@vindex calendar-daylight-savings-starts-time
-@vindex calendar-daylight-savings-ends-time
- The variable @code{calendar-daylight-savings-starts-time} and the
-variable @code{calendar-daylight-savings-ends-time} specify the number
-of minutes after midnight local time when the transition to and from
-daylight savings time should occur. For Cambridge, both variables'
-values are 120.
-
-@node Diary Customizing
-@section Customizing the Diary
-
-@vindex holidays-in-diary-buffer
- Ordinarily, the mode line of the diary buffer window indicates any
-holidays that fall on the date of the diary entries. The process of
-checking for holidays can take several seconds, so including holiday
-information delays the display of the diary buffer noticeably. If you'd
-prefer to have a faster display of the diary buffer but without the
-holiday information, set the variable @code{holidays-in-diary-buffer} to
-@code{nil}.@refill
-
-@vindex number-of-diary-entries
- The variable @code{number-of-diary-entries} controls the number of
-days of diary entries to be displayed at one time. It affects the
-initial display when @code{view-diary-entries-initially} is @code{t}, as
-well as the command @kbd{M-x diary}. For example, the default value is
-1, which says to display only the current day's diary entries. If the
-value is 2, both the current day's and the next day's entries are
-displayed. The value can also be a vector of seven elements: for
-example, if the value is @code{[0 2 2 2 2 4 1]} then no diary entries
-appear on Sunday, the current date's and the next day's diary entries
-appear Monday through Thursday, Friday through Monday's entries appear
-on Friday, while on Saturday only that day's entries appear.
-
-@vindex print-diary-entries-hook
-@findex print-diary-entries
- The variable @code{print-diary-entries-hook} is a normal hook run
-after preparation of a temporary buffer containing just the diary
-entries currently visible in the diary buffer. (The other, irrelevant
-diary entries are really absent from the temporary buffer; in the diary
-buffer, they are merely hidden.) The default value of this hook does
-the printing with the command @code{lpr-buffer}. If you want to use a
-different command to do the printing, just change the value of this
-hook. Other uses might include, for example, rearranging the lines into
-order by day and time.
-
-@vindex diary-date-forms
- You can customize the form of dates in your diary file, if neither the
-standard American nor European styles suits your needs, by setting the
-variable @code{diary-date-forms}. This variable is a list of patterns
-for recognizing a date. Each date pattern is a list whose elements may
-be regular expressions (@pxref{Regular Expressions,,, elisp, the Emacs
-Lisp Reference Manual}) or the symbols @code{month}, @code{day},
-@code{year}, @code{monthname}, and @code{dayname}. All these elements
-serve as patterns that match certain kinds of text in the diary file.
-In order for the date pattern, as a whole, to match, all of its elements
-must match consecutively.
-
- A regular expression in a date pattern matches in its usual fashion,
-using the standard syntax table altered so that @samp{*} is a word
-constituent.
-
- The symbols @code{month}, @code{day}, @code{year}, @code{monthname},
-and @code{dayname} match the month number, day number, year number,
-month name, and day name of the date being considered. The symbols that
-match numbers allow leading zeros; those that match names allow
-three-letter abbreviations and capitalization. All the symbols can
-match @samp{*}; since @samp{*} in a diary entry means ``any day'', ``any
-month'', and so on, it should match regardless of the date being
-considered.
-
- The default value of @code{diary-date-forms} in the American style is
-this:
-
-@example
-((month "/" day "[^/0-9]")
- (month "/" day "/" year "[^0-9]")
- (monthname " *" day "[^,0-9]")
- (monthname " *" day ", *" year "[^0-9]")
- (dayname "\\W"))
-@end example
-
- The date patterns in the list must be @emph{mutually exclusive} and
-must not match any portion of the diary entry itself, just the date and
-one character of whitespace. If, to be mutually exclusive, the pattern
-must match a portion of the diary entry text---beyond the whitespace
-that ends the date---then the first element of the date pattern
-@emph{must} be @code{backup}. This causes the date recognizer to back
-up to the beginning of the current word of the diary entry, after
-finishing the match. Even if you use @code{backup}, the date pattern
-must absolutely not match more than a portion of the first word of the
-diary entry. The default value of @code{diary-date-forms} in the
-European style is this list:
-
-@example
-((day "/" month "[^/0-9]")
- (day "/" month "/" year "[^0-9]")
- (backup day " *" monthname "\\W+\\<[^*0-9]")
- (day " *" monthname " *" year "[^0-9]")
- (dayname "\\W"))
-@end example
-
-@noindent
-Notice the use of @code{backup} in the third pattern, because it needs
-to match part of a word beyond the date itself to distinguish it from
-the fourth pattern.
-
-@node Hebrew/Islamic Entries
-@section Hebrew- and Islamic-Date Diary Entries
-
- Your diary file can have entries based on Hebrew or Islamic dates, as
-well as entries based on the world-standard Gregorian calendar.
-However, because recognition of such entries is time-consuming and most
-people don't use them, you must explicitly enable their use. If you
-want the diary to recognize Hebrew-date diary entries, for example,
-you must do this:
-
-@vindex nongregorian-diary-listing-hook
-@vindex nongregorian-diary-marking-hook
-@findex list-hebrew-diary-entries
-@findex mark-hebrew-diary-entries
-@smallexample
-(add-hook 'nongregorian-diary-listing-hook 'list-hebrew-diary-entries)
-(add-hook 'nongregorian-diary-marking-hook 'mark-hebrew-diary-entries)
-@end smallexample
-
-@noindent
-If you want Islamic-date entries, do this:
-
-@findex list-islamic-diary-entries
-@findex mark-islamic-diary-entries
-@smallexample
-(add-hook 'nongregorian-diary-listing-hook 'list-islamic-diary-entries)
-(add-hook 'nongregorian-diary-marking-hook 'mark-islamic-diary-entries)
-@end smallexample
-
- Hebrew- and Islamic-date diary entries have the same formats as
-Gregorian-date diary entries, except that @samp{H} precedes a Hebrew
-date and @samp{I} precedes an Islamic date. Moreover, because the
-Hebrew and Islamic month names are not uniquely specified by the first
-three letters, you may not abbreviate them. For example, a diary entry
-for the Hebrew date Heshvan 25 could look like this:
-
-@smallexample
-HHeshvan 25 Happy Hebrew birthday!
-@end smallexample
-
-@noindent
-and would appear in the diary for any date that corresponds to Heshvan 25
-on the Hebrew calendar. And here is an Islamic-date diary entry that matches
-Dhu al-Qada 25:
-
-@smallexample
-IDhu al-Qada 25 Happy Islamic birthday!
-@end smallexample
-
- As with Gregorian-date diary entries, Hebrew- and Islamic-date entries
-are nonmarking if they are preceded with an ampersand (@samp{&}).
-
- Here is a table of commands used in the calendar to create diary entries
-that match the selected date and other dates that are similar in the Hebrew
-or Islamic calendar:
-
-@table @kbd
-@item i h d
-Add a diary entry for the Hebrew date corresponding to the selected date
-(@code{insert-hebrew-diary-entry}).
-@item i h m
-Add a diary entry for the day of the Hebrew month corresponding to the
-selected date (@code{insert-monthly-hebrew-diary-entry}). This diary
-entry matches any date that has the same Hebrew day-within-month as the
-selected date.
-@item i h y
-Add a diary entry for the day of the Hebrew year corresponding to the
-selected date (@code{insert-yearly-hebrew-diary-entry}). This diary
-entry matches any date which has the same Hebrew month and day-within-month
-as the selected date.
-@item i i d
-Add a diary entry for the Islamic date corresponding to the selected date
-(@code{insert-islamic-diary-entry}).
-@item i i m
-Add a diary entry for the day of the Islamic month corresponding to the
-selected date (@code{insert-monthly-islamic-diary-entry}).
-@item i i y
-Add a diary entry for the day of the Islamic year corresponding to the
-selected date (@code{insert-yearly-islamic-diary-entry}).
-@end table
-
-@findex insert-hebrew-diary-entry
-@findex insert-monthly-hebrew-diary-entry
-@findex insert-yearly-hebrew-diary-entry
-@findex insert-islamic-diary-entry
-@findex insert-monthly-islamic-diary-entry
-@findex insert-yearly-islamic-diary-entry
- These commands work much like the corresponding commands for ordinary
-diary entries: they apply to the date that point is on in the calendar
-window, and what they do is insert just the date portion of a diary entry
-at the end of your diary file. You must then insert the rest of the
-diary entry.
-
-@node Fancy Diary Display
-@section Fancy Diary Display
-@vindex diary-display-hook
-@findex simple-diary-display
-
- Diary display works by preparing the diary buffer and then running the
-hook @code{diary-display-hook}. The default value of this hook
-(@code{simple-diary-display}) hides the irrelevant diary entries and
-then displays the buffer. However, if you specify the hook as follows,
-
-@cindex diary buffer
-@findex fancy-diary-display
-@example
-(add-hook 'diary-display-hook 'fancy-diary-display)
-@end example
-
-@noindent
-this enables fancy diary display. It displays diary entries and
-holidays by copying them into a special buffer that exists only for the
-sake of display. Copying to a separate buffer provides an opportunity
-to change the displayed text to make it prettier---for example, to sort
-the entries by the dates they apply to.
-
- As with simple diary display, you can print a hard copy of the buffer
-with @code{print-diary-entries}. To print a hard copy of a day-by-day
-diary for a week, position point on Sunday of that week, type
-@kbd{7 d}, and then do @kbd{M-x print-diary-entries}. As usual, the
-inclusion of the holidays slows down the display slightly; you can speed
-things up by setting the variable @code{holidays-in-diary-buffer} to
-@code{nil}.
-
-@vindex diary-list-include-blanks
- Ordinarily, the fancy diary buffer does not show days for which there are
-no diary entries, even if that day is a holiday. If you want such days to be
-shown in the fancy diary buffer, set the variable
-@code{diary-list-include-blanks} to @code{t}.@refill
-
-@cindex sorting diary entries
- If you use the fancy diary display, you can use the normal hook
-@code{list-diary-entries-hook} to sort each day's diary entries by their
-time of day. Here's how:
-
-@findex sort-diary-entries
-@example
-(add-hook 'list-diary-entries-hook 'sort-diary-entries t)
-@end example
-
-@noindent
-For each day, this sorts diary entries that begin with a recognizable
-time of day according to their times. Diary entries without times come
-first within each day.
-
- Fancy diary display also has the ability to process included diary
-files. This permits a group of people to share a diary file for events
-that apply to all of them. Lines in the diary file of this form:
-
-@smallexample
-#include "@var{filename}"
-@end smallexample
-
-@noindent
-includes the diary entries from the file @var{filename} in the fancy
-diary buffer. The include mechanism is recursive, so that included files
-can include other files, and so on; you must be careful not to have a
-cycle of inclusions, of course. Here is how to enable the include
-facility:
-
-@vindex list-diary-entries-hook
-@vindex mark-diary-entries-hook
-@findex include-other-diary-files
-@findex mark-included-diary-files
-@smallexample
-(add-hook 'list-diary-entries-hook 'include-other-diary-files)
-(add-hook 'mark-diary-entries-hook 'mark-included-diary-files)
-@end smallexample
-
-The include mechanism works only with the fancy diary display, because
-ordinary diary display shows the entries directly from your diary file.
-
-@node Sexp Diary Entries
-@section Sexp Entries and the Fancy Diary Display
-@cindex sexp diary entries
-
- Sexp diary entries allow you to do more than just have complicated
-conditions under which a diary entry applies. If you use the fancy
-diary display, sexp entries can generate the text of the entry depending
-on the date itself. For example, an anniversary diary entry can insert
-the number of years since the anniversary date into the text of the
-diary entry. Thus the @samp{%d} in this dairy entry:
-
-@findex diary-anniversary
-@smallexample
-%%(diary-anniversary 10 31 1948) Arthur's birthday (%d years old)
-@end smallexample
-
-@noindent
-gets replaced by the age, so on October 31, 1990 the entry appears in
-the fancy diary buffer like this:
-
-@smallexample
-Arthur's birthday (42 years old)
-@end smallexample
-
-@noindent
-If the diary file instead contains this entry:
-
-@smallexample
-%%(diary-anniversary 10 31 1948) Arthur's %d%s birthday
-@end smallexample
-
-@noindent
-the entry in the fancy diary buffer for October 31, 1990 appears like this:
-
-@smallexample
-Arthur's 42nd birthday
-@end smallexample
-
- Similarly, cyclic diary entries can interpolate the number of repetitions
-that have occurred:
-
-@findex diary-cyclic
-@smallexample
-%%(diary-cyclic 50 1 1 1990) Renew medication (%d%s time)
-@end smallexample
-
-@noindent
-looks like this:
-
-@smallexample
-Renew medication (5th time)
-@end smallexample
-
-@noindent
-in the fancy diary display on September 8, 1990.
-
- There is an early reminder diary sexp that includes its entry in the
-diary not only on the date of occurrence, but also on earlier dates.
-For example, if you want a reminder a week before your anniversary, you
-can use
-
-@findex diary-remind
-@smallexample
-%%(diary-remind '(diary-anniversary 12 22 1968) 7) Ed's anniversary
-@end smallexample
-
-@noindent
-and the fancy diary will show
-@smallexample
-Ed's anniversary
-@end smallexample
-@noindent
-both on December 15 and on December 22.
-
-@findex diary-date
- The function @code{diary-date} applies to dates described by a month,
-day, year combination, each of which can be an integer, a list of
-integers, or @code{t}. The value @code{t} means all values. For
-example,
-
-@smallexample
-%%(diary-date '(10 11 12) 22 t) Rake leaves
-@end smallexample
-
-@noindent
-causes the fancy diary to show
-
-@smallexample
-Rake leaves
-@end smallexample
-
-@noindent
-on October 22, November 22, and December 22 of every year.
-
-@findex diary-float
- The function @code{diary-float} allows you to describe diary entries
-that apply to dates like the third Friday of November, or the last
-Tuesday in April. The parameters are the @var{month}, @var{dayname},
-and an index @var{n}. The entry appears on the @var{n}th @var{dayname}
-of @var{month}, where @var{dayname}=0 means Sunday, 1 means Monday, and
-so on. If @var{n} is negative it counts backward from the end of
-@var{month}. The value of @var{month} can be a list of months, a single
-month, or @code{t} to specify all months. You can also use an optional
-parameter @var{day} to specify the @var{n}th @var{dayname} of
-@var{month} on or after/before @var{day}; the value of @var{day} defaults
-to 1 if @var{n} is positive and to the last day of @var{month} if
-@var{n} is negative. For example,
-
-@smallexample
-%%(diary-float t 1 -1) Pay rent
-@end smallexample
-
-@noindent
-causes the fancy diary to show
-
-@smallexample
-Pay rent
-@end smallexample
-
-@noindent
-on the last Monday of every month.
-
- The generality of sexp diary entries lets you specify any diary
-entry that you can describe algorithmically. A sexp diary entry
-contains an expression that computes whether the entry applies to any
-given date. If its value is non-@code{nil}, the entry applies to that
-date; otherwise, it does not. The expression can use the variable
-@code{date} to find the date being considered; its value is a list
-(@var{month} @var{day} @var{year}) that refers to the Gregorian
-calendar.
-
- The sexp diary entry applies to a date when the expression's value
-is non-@code{nil}, but some values have more specific meanings. If
-the value is a string, that string is a description of the event which
-occurs on that date. The value can also have the form
-@code{(@var{mark} . @var{string})}; then @var{mark} specifies how to
-mark the date in the calendar, and @var{string} is the description of
-the event. If @var{mark} is a single-character string, that character
-appears next to the date in the calendar. If @var{mark} is a face
-name, the date is displayed in that face. If @var{mark} is
-@code{nil}, that specifies no particular highlighting for the date.
-
- Suppose you get paid on the 21st of the month if it is a weekday, and
-on the Friday before if the 21st is on a weekend. Here is how to write
-a sexp diary entry that matches those dates:
-
-@smallexample
-&%%(let ((dayname (calendar-day-of-week date))
- (day (car (cdr date))))
- (or (and (= day 21) (memq dayname '(1 2 3 4 5)))
- (and (memq day '(19 20)) (= dayname 5)))
- ) Pay check deposited
-@end smallexample
-
- The following sexp diary entries take advantage of the ability (in the fancy
-diary display) to concoct diary entries whose text varies based on the date:
-
-@findex diary-sunrise-sunset
-@findex diary-phases-of-moon
-@findex diary-day-of-year
-@findex diary-iso-date
-@findex diary-julian-date
-@findex diary-astro-day-number
-@findex diary-hebrew-date
-@findex diary-islamic-date
-@findex diary-french-date
-@findex diary-mayan-date
-@table @code
-@item %%(diary-sunrise-sunset)
-Make a diary entry for the local times of today's sunrise and sunset.
-@item %%(diary-phases-of-moon)
-Make a diary entry for the phases (quarters) of the moon.
-@item %%(diary-day-of-year)
-Make a diary entry with today's day number in the current year and the number
-of days remaining in the current year.
-@item %%(diary-iso-date)
-Make a diary entry with today's equivalent ISO commercial date.
-@item %%(diary-julian-date)
-Make a diary entry with today's equivalent date on the Julian calendar.
-@item %%(diary-astro-day-number)
-Make a diary entry with today's equivalent astronomical (Julian) day number.
-@item %%(diary-hebrew-date)
-Make a diary entry with today's equivalent date on the Hebrew calendar.
-@item %%(diary-islamic-date)
-Make a diary entry with today's equivalent date on the Islamic calendar.
-@item %%(diary-french-date)
-Make a diary entry with today's equivalent date on the French Revolutionary
-calendar.
-@item %%(diary-mayan-date)
-Make a diary entry with today's equivalent date on the Mayan calendar.
-@end table
-
-@noindent
-Thus including the diary entry
-
-@example
-&%%(diary-hebrew-date)
-@end example
-
-@noindent
-causes every day's diary display to contain the equivalent date on the
-Hebrew calendar, if you are using the fancy diary display. (With simple
-diary display, the line @samp{&%%(diary-hebrew-date)} appears in the
-diary for any date, but does nothing particularly useful.)
-
- These functions can be used to construct sexp diary entries based on
-the Hebrew calendar in certain standard ways:
-
-@cindex rosh hodesh
-@findex diary-rosh-hodesh
-@cindex parasha, weekly
-@findex diary-parasha
-@cindex candle lighting times
-@findex diary-sabbath-candles
-@cindex omer count
-@findex diary-omer
-@cindex yahrzeits
-@findex diary-yahrzeit
-@table @code
-@item %%(diary-rosh-hodesh)
-Make a diary entry that tells the occurrence and ritual announcement of each
-new Hebrew month.
-@item %%(diary-parasha)
-Make a Saturday diary entry that tells the weekly synagogue scripture reading.
-@item %%(diary-sabbath-candles)
-Make a Friday diary entry that tells the @emph{local time} of Sabbath
-candle lighting.
-@item %%(diary-omer)
-Make a diary entry that gives the omer count, when appropriate.
-@item %%(diary-yahrzeit @var{month} @var{day} @var{year}) @var{name}
-Make a diary entry marking the anniversary of a date of death. The date
-is the @emph{Gregorian} (civil) date of death. The diary entry appears
-on the proper Hebrew calendar anniversary and on the day before. (In
-the European style, the order of the parameters is changed to @var{day},
-@var{month}, @var{year}.)
-@end table
-
- All the functions documented above take an optional argument
-@var{mark} which specifies how to mark the date in the calendar display.
-If one of these functions decides that it applies to a certain date,
-it returns a value that contains @var{mark}.
-
-@node Emerge
-@chapter Merging Files with Emerge
-@cindex Emerge
-@cindex merging files
-
- It's not unusual for programmers to get their signals crossed and
-modify the same program in two different directions. To recover from
-this confusion, you need to merge the two versions. Emerge makes this
-easier. For other ways to compare files, see @ref{Comparing Files,,,
-emacs, the Emacs Manual} and @ref{Top, Ediff,, ediff, The Ediff
-Manual}.
-
-@menu
-* Overview of Emerge:: How to start Emerge. Basic concepts.
-* Submodes of Emerge:: Fast mode vs. Edit mode.
- Skip Prefers mode and Auto Advance mode.
-* State of Difference:: You do the merge by specifying state A or B
- for each difference.
-* Merge Commands:: Commands for selecting a difference,
- changing states of differences, etc.
-* Exiting Emerge:: What to do when you've finished the merge.
-* Combining in Emerge:: How to keep both alternatives for a difference.
-* Fine Points of Emerge:: Misc.
-@end menu
-
-@node Overview of Emerge
-@section Overview of Emerge
-
- To start Emerge, run one of these four commands:
-
-@table @kbd
-@item M-x emerge-files
-@findex emerge-files
-Merge two specified files.
-
-@item M-x emerge-files-with-ancestor
-@findex emerge-files-with-ancestor
-Merge two specified files, with reference to a common ancestor.
-
-@item M-x emerge-buffers
-@findex emerge-buffers
-Merge two buffers.
-
-@item M-x emerge-buffers-with-ancestor
-@findex emerge-buffers-with-ancestor
-Merge two buffers with reference to a common ancestor in a third
-buffer.
-@end table
-
-@cindex merge buffer (Emerge)
-@cindex A and B buffers (Emerge)
- The Emerge commands compare two files or buffers, and display the
-comparison in three buffers: one for each input text (the @dfn{A buffer}
-and the @dfn{B buffer}), and one (the @dfn{merge buffer}) where merging
-takes place. The merge buffer shows the full merged text, not just the
-differences. Wherever the two input texts differ, you can choose which
-one of them to include in the merge buffer.
-
- The Emerge commands that take input from existing buffers use only
-the accessible portions of those buffers, if they are narrowed.
-@xref{Narrowing,,, emacs, the Emacs Manual}.
-
-
- If a common ancestor version is available, from which the two texts to
-be merged were both derived, Emerge can use it to guess which
-alternative is right. Wherever one current version agrees with the
-ancestor, Emerge presumes that the other current version is a deliberate
-change which should be kept in the merged version. Use the
-@samp{with-ancestor} commands if you want to specify a common ancestor
-text. These commands read three file or buffer names---variant A,
-variant B, and the common ancestor.
-
- After the comparison is done and the buffers are prepared, the
-interactive merging starts. You control the merging by typing special
-@dfn{merge commands} in the merge buffer (@pxref{Merge Commands}).
-For each run of differences between the input texts, you can choose
-which one of them to keep, or edit them both together.
-
- The merge buffer uses a special major mode, Emerge mode, with commands
-for making these choices. But you can also edit the buffer with
-ordinary Emacs commands.
-
- At any given time, the attention of Emerge is focused on one
-particular difference, called the @dfn{selected} difference. This
-difference is marked off in the three buffers like this:
-
-@example
-vvvvvvvvvvvvvvvvvvvv
-@var{text that differs}
-^^^^^^^^^^^^^^^^^^^^
-@end example
-
-@noindent
-Emerge numbers all the differences sequentially and the mode
-line always shows the number of the selected difference.
-
- Normally, the merge buffer starts out with the A version of the text.
-But when the A version of a difference agrees with the common ancestor,
-then the B version is initially preferred for that difference.
-
- Emerge leaves the merged text in the merge buffer when you exit. At
-that point, you can save it in a file with @kbd{C-x C-w}. If you give a
-numeric argument to @code{emerge-files} or
-@code{emerge-files-with-ancestor}, it reads the name of the output file
-using the minibuffer. (This is the last file name those commands read.)
-Then exiting from Emerge saves the merged text in the output file.
-
- Normally, Emerge commands save the output buffer in its file when you
-exit. If you abort Emerge with @kbd{C-]}, the Emerge command does not
-save the output buffer, but you can save it yourself if you wish.
-
-@node Submodes of Emerge
-@section Submodes of Emerge
-
- You can choose between two modes for giving merge commands: Fast mode
-and Edit mode. In Fast mode, basic merge commands are single
-characters, but ordinary Emacs commands are disabled. This is
-convenient if you use only merge commands. In Edit mode, all merge
-commands start with the prefix key @kbd{C-c C-c}, and the normal Emacs
-commands are also available. This allows editing the merge buffer, but
-slows down Emerge operations.
-
- Use @kbd{e} to switch to Edit mode, and @kbd{C-c C-c f} to switch to
-Fast mode. The mode line indicates Edit and Fast modes with @samp{E}
-and @samp{F}.
-
- Emerge has two additional submodes that affect how particular merge
-commands work: Auto Advance mode and Skip Prefers mode.
-
- If Auto Advance mode is in effect, the @kbd{a} and @kbd{b} commands
-advance to the next difference. This lets you go through the merge
-faster as long as you simply choose one of the alternatives from the
-input. The mode line indicates Auto Advance mode with @samp{A}.
-
- If Skip Prefers mode is in effect, the @kbd{n} and @kbd{p} commands
-skip over differences in states prefer-A and prefer-B (@pxref{State of
-Difference}). Thus you see only differences for which neither version
-is presumed ``correct.'' The mode line indicates Skip Prefers mode with
-@samp{S}.
-
-@findex emerge-auto-advance-mode
-@findex emerge-skip-prefers-mode
- Use the command @kbd{s a} (@code{emerge-auto-advance-mode}) to set or
-clear Auto Advance mode. Use @kbd{s s}
-(@code{emerge-skip-prefers-mode}) to set or clear Skip Prefers mode.
-These commands turn on the mode with a positive argument, turns it off
-with a negative or zero argument, and toggle the mode with no argument.
-
-@node State of Difference
-@section State of a Difference
-
- In the merge buffer, a difference is marked with lines of @samp{v} and
-@samp{^} characters. Each difference has one of these seven states:
-
-@table @asis
-@item A
-The difference is showing the A version. The @kbd{a} command always
-produces this state; the mode line indicates it with @samp{A}.
-
-@item B
-The difference is showing the B version. The @kbd{b} command always
-produces this state; the mode line indicates it with @samp{B}.
-
-@item default-A
-@itemx default-B
-The difference is showing the A or the B state by default, because you
-haven't made a choice. All differences start in the default-A state
-(and thus the merge buffer is a copy of the A buffer), except those for
-which one alternative is ``preferred'' (see below).
-
-When you select a difference, its state changes from default-A or
-default-B to plain A or B. Thus, the selected difference never has
-state default-A or default-B, and these states are never displayed in
-the mode line.
-
-The command @kbd{d a} chooses default-A as the default state, and @kbd{d
-b} chooses default-B. This chosen default applies to all differences
-which you haven't ever selected and for which no alternative is preferred.
-If you are moving through the merge sequentially, the differences you
-haven't selected are those following the selected one. Thus, while
-moving sequentially, you can effectively make the A version the default
-for some sections of the merge buffer and the B version the default for
-others by using @kbd{d a} and @kbd{d b} between sections.
-
-@item prefer-A
-@itemx prefer-B
-The difference is showing the A or B state because it is
-@dfn{preferred}. This means that you haven't made an explicit choice,
-but one alternative seems likely to be right because the other
-alternative agrees with the common ancestor. Thus, where the A buffer
-agrees with the common ancestor, the B version is preferred, because
-chances are it is the one that was actually changed.
-
-These two states are displayed in the mode line as @samp{A*} and @samp{B*}.
-
-@item combined
-The difference is showing a combination of the A and B states, as a
-result of the @kbd{x c} or @kbd{x C} commands.
-
-Once a difference is in this state, the @kbd{a} and @kbd{b} commands
-don't do anything to it unless you give them a numeric argument.
-
-The mode line displays this state as @samp{comb}.
-@end table
-
-@node Merge Commands
-@section Merge Commands
-
- Here are the Merge commands for Fast mode; in Edit mode, precede them
-with @kbd{C-c C-c}:
-
-@table @kbd
-@item p
-Select the previous difference.
-
-@item n
-Select the next difference.
-
-@item a
-Choose the A version of this difference.
-
-@item b
-Choose the B version of this difference.
-
-@item C-u @var{n} j
-Select difference number @var{n}.
-
-@item .
-Select the difference containing point. You can use this command in the
-merge buffer or in the A or B buffer.
-
-@item q
-Quit---finish the merge.
-
-@item C-]
-Abort---exit merging and do not save the output.
-
-@item f
-Go into Fast mode. (In Edit mode, this is actually @kbd{C-c C-c f}.)
+@iftex
+@c ``Picture Mode'' is a chapter, not a section, so it's outside @raisesections.
+@include picture-xtra.texi
-@item e
-Go into Edit mode.
+@raisesections
+@include arevert-xtra.texi
-@item l
-Recenter (like @kbd{C-l}) all three windows.
+@include dired-xtra.texi
-@item -
-Specify part of a prefix numeric argument.
+@include cal-xtra.texi
-@item @var{digit}
-Also specify part of a prefix numeric argument.
+@include emerge-xtra.texi
-@item d a
-Choose the A version as the default from here down in
-the merge buffer.
+@include vc-xtra.texi
-@item d b
-Choose the B version as the default from here down in
-the merge buffer.
+@include fortran-xtra.texi
-@item c a
-Copy the A version of this difference into the kill ring.
+@include msdog-xtra.texi
-@item c b
-Copy the B version of this difference into the kill ring.
-
-@item i a
-Insert the A version of this difference at point.
-
-@item i b
-Insert the B version of this difference at point.
-
-@item m
-Put point and mark around the difference.
-
-@item ^
-Scroll all three windows down (like @kbd{M-v}).
-
-@item v
-Scroll all three windows up (like @kbd{C-v}).
-
-@item <
-Scroll all three windows left (like @kbd{C-x <}).
-
-@item >
-Scroll all three windows right (like @kbd{C-x >}).
-
-@item |
-Reset horizontal scroll on all three windows.
-
-@item x 1
-Shrink the merge window to one line. (Use @kbd{C-u l} to restore it
-to full size.)
-
-@item x c
-Combine the two versions of this difference (@pxref{Combining in
-Emerge}).
-
-@item x f
-Show the names of the files/buffers Emerge is operating on, in a Help
-window. (Use @kbd{C-u l} to restore windows.)
-
-@item x j
-Join this difference with the following one.
-(@kbd{C-u x j} joins this difference with the previous one.)
-
-@item x s
-Split this difference into two differences. Before you use this
-command, position point in each of the three buffers at the place where
-you want to split the difference.
-
-@item x t
-Trim identical lines off the top and bottom of the difference.
-Such lines occur when the A and B versions are
-identical but differ from the ancestor version.
-@end table
-
-@node Exiting Emerge
-@section Exiting Emerge
-
- The @kbd{q} command (@code{emerge-quit}) finishes the merge, storing
-the results into the output file if you specified one. It restores the
-A and B buffers to their proper contents, or kills them if they were
-created by Emerge and you haven't changed them. It also disables the
-Emerge commands in the merge buffer, since executing them later could
-damage the contents of the various buffers.
-
- @kbd{C-]} aborts the merge. This means exiting without writing the
-output file. If you didn't specify an output file, then there is no
-real difference between aborting and finishing the merge.
-
- If the Emerge command was called from another Lisp program, then its
-return value is @code{t} for successful completion, or @code{nil} if you
-abort.
-
-@node Combining in Emerge
-@section Combining the Two Versions
-
- Sometimes you want to keep @emph{both} alternatives for a particular
-difference. To do this, use @kbd{x c}, which edits the merge buffer
-like this:
-
-@example
-@group
-#ifdef NEW
-@var{version from A buffer}
-#else /* not NEW */
-@var{version from B buffer}
-#endif /* not NEW */
-@end group
-@end example
-
-@noindent
-@vindex emerge-combine-versions-template
-While this example shows C preprocessor conditionals delimiting the two
-alternative versions, you can specify the strings to use by setting
-the variable @code{emerge-combine-versions-template} to a string of your
-choice. In the string, @samp{%a} says where to put version A, and
-@samp{%b} says where to put version B. The default setting, which
-produces the results shown above, looks like this:
-
-@example
-@group
-"#ifdef NEW\n%a#else /* not NEW */\n%b#endif /* not NEW */\n"
-@end group
-@end example
-
-@node Fine Points of Emerge
-@section Fine Points of Emerge
-
- During the merge, you mustn't try to edit the A and B buffers yourself.
-Emerge modifies them temporarily, but ultimately puts them back the way
-they were.
-
- You can have any number of merges going at once---just don't use any one
-buffer as input to more than one merge at once, since the temporary
-changes made in these buffers would get in each other's way.
-
- Starting Emerge can take a long time because it needs to compare the
-files fully. Emacs can't do anything else until @code{diff} finishes.
-Perhaps in the future someone will change Emerge to do the comparison in
-the background when the input files are large---then you could keep on
-doing other things with Emacs until Emerge is ready to accept
-commands.
-
-@vindex emerge-startup-hook
- After setting up the merge, Emerge runs the hook
-@code{emerge-startup-hook}. @xref{Hooks,,, emacs, the Emacs Manual}.
-
-@node Picture Mode
-@chapter Editing Pictures
-@cindex pictures
-@cindex making pictures out of text characters
-@findex edit-picture
-
- To edit a picture made out of text characters (for example, a picture
-of the division of a register into fields, as a comment in a program),
-use the command @kbd{M-x edit-picture} to enter Picture mode.
-
- In Picture mode, editing is based on the @dfn{quarter-plane} model of
-text, according to which the text characters lie studded on an area that
-stretches infinitely far to the right and downward. The concept of the end
-of a line does not exist in this model; the most you can say is where the
-last nonblank character on the line is found.
-
- Of course, Emacs really always considers text as a sequence of
-characters, and lines really do have ends. But Picture mode replaces
-the most frequently-used commands with variants that simulate the
-quarter-plane model of text. They do this by inserting spaces or by
-converting tabs to spaces.
-
- Most of the basic editing commands of Emacs are redefined by Picture mode
-to do essentially the same thing but in a quarter-plane way. In addition,
-Picture mode defines various keys starting with the @kbd{C-c} prefix to
-run special picture editing commands.
-
- One of these keys, @kbd{C-c C-c}, is particularly important. Often a
-picture is part of a larger file that is usually edited in some other
-major mode. @kbd{M-x edit-picture} records the name of the previous
-major mode so you can use the @kbd{C-c C-c} command
-(@code{picture-mode-exit}) later to go back to that mode. @kbd{C-c C-c}
-also deletes spaces from the ends of lines, unless given a numeric
-argument.
-
- The special commands of Picture mode all work in other modes (provided
-the @file{picture} library is loaded), but are not bound to keys except
-in Picture mode. The descriptions below talk of moving ``one column''
-and so on, but all the picture mode commands handle numeric arguments as
-their normal equivalents do.
-
-@vindex picture-mode-hook
- Turning on Picture mode runs the hook @code{picture-mode-hook}.
-Additional extensions to Picture mode can be found in
-@file{artist.el}.
-
-@menu
-* Basic Picture:: Basic concepts and simple commands of Picture Mode.
-* Insert in Picture:: Controlling direction of cursor motion
- after "self-inserting" characters.
-* Tabs in Picture:: Various features for tab stops and indentation.
-* Rectangles in Picture:: Clearing and superimposing rectangles.
-@end menu
-
-@node Basic Picture
-@section Basic Editing in Picture Mode
-
-@findex picture-forward-column
-@findex picture-backward-column
-@findex picture-move-down
-@findex picture-move-up
-@cindex editing in Picture mode
-
- Most keys do the same thing in Picture mode that they usually do, but
-do it in a quarter-plane style. For example, @kbd{C-f} is rebound to
-run @code{picture-forward-column}, a command which moves point one
-column to the right, inserting a space if necessary so that the actual
-end of the line makes no difference. @kbd{C-b} is rebound to run
-@code{picture-backward-column}, which always moves point left one
-column, converting a tab to multiple spaces if necessary. @kbd{C-n} and
-@kbd{C-p} are rebound to run @code{picture-move-down} and
-@code{picture-move-up}, which can either insert spaces or convert tabs
-as necessary to make sure that point stays in exactly the same column.
-@kbd{C-e} runs @code{picture-end-of-line}, which moves to after the last
-nonblank character on the line. There is no need to change @kbd{C-a},
-as the choice of screen model does not affect beginnings of
-lines.
-
-@findex picture-newline
- Insertion of text is adapted to the quarter-plane screen model
-through the use of Overwrite mode (@pxref{Minor Modes,,, emacs, the
-Emacs Manual}.) Self-inserting characters replace existing text,
-column by column, rather than pushing existing text to the right.
-@key{RET} runs @code{picture-newline}, which just moves to the
-beginning of the following line so that new text will replace that
-line.
-
-@findex picture-backward-clear-column
-@findex picture-clear-column
-@findex picture-clear-line
- In Picture mode, the commands that normally delete or kill text,
-instead erase text (replacing it with spaces). @key{DEL}
-(@code{picture-backward-clear-column}) replaces the preceding
-character with a space rather than removing it; this moves point
-backwards. @kbd{C-d} (@code{picture-clear-column}) replaces the next
-character or characters with spaces, but does not move point. (If you
-want to clear characters to spaces and move forward over them, use
-@key{SPC}.) @kbd{C-k} (@code{picture-clear-line}) really kills the
-contents of lines, but does not delete the newlines from the buffer.
-
-@findex picture-open-line
- To do actual insertion, you must use special commands. @kbd{C-o}
-(@code{picture-open-line}) creates a blank line after the current
-line; it never splits a line. @kbd{C-M-o} (@code{split-line}) makes
-sense in Picture mode, so it is not changed. @kbd{C-j}
-(@code{picture-duplicate-line}) inserts another line with the same
-contents below the current line.
-
-@kindex C-c C-d @r{(Picture mode)}
- To do actual deletion in Picture mode, use @kbd{C-w}, @kbd{C-c C-d}
-(which is defined as @code{delete-char}, as @kbd{C-d} is in other
-modes), or one of the picture rectangle commands (@pxref{Rectangles in
-Picture}).
-
-@node Insert in Picture
-@section Controlling Motion after Insert
-
-@findex picture-movement-up
-@findex picture-movement-down
-@findex picture-movement-left
-@findex picture-movement-right
-@findex picture-movement-nw
-@findex picture-movement-ne
-@findex picture-movement-sw
-@findex picture-movement-se
-@kindex C-c < @r{(Picture mode)}
-@kindex C-c > @r{(Picture mode)}
-@kindex C-c ^ @r{(Picture mode)}
-@kindex C-c . @r{(Picture mode)}
-@kindex C-c ` @r{(Picture mode)}
-@kindex C-c ' @r{(Picture mode)}
-@kindex C-c / @r{(Picture mode)}
-@kindex C-c \ @r{(Picture mode)}
- Since ``self-inserting'' characters in Picture mode overwrite and move
-point, there is no essential restriction on how point should be moved.
-Normally point moves right, but you can specify any of the eight
-orthogonal or diagonal directions for motion after a ``self-inserting''
-character. This is useful for drawing lines in the buffer.
-
-@table @kbd
-@item C-c <
-@itemx C-c @key{LEFT}
-Move left after insertion (@code{picture-movement-left}).
-@item C-c >
-@itemx C-c @key{RIGHT}
-Move right after insertion (@code{picture-movement-right}).
-@item C-c ^
-@itemx C-c @key{UP}
-Move up after insertion (@code{picture-movement-up}).
-@item C-c .
-@itemx C-c @key{DOWN}
-Move down after insertion (@code{picture-movement-down}).
-@item C-c `
-@itemx C-c @key{HOME}
-Move up and left (``northwest'') after insertion (@code{picture-movement-nw}).
-@item C-c '
-@itemx C-c @key{PAGEUP}
-Move up and right (``northeast'') after insertion
-(@code{picture-movement-ne}).
-@item C-c /
-@itemx C-c @key{END}
-Move down and left (``southwest'') after insertion
-@*(@code{picture-movement-sw}).
-@item C-c \
-@itemx C-c @key{PAGEDOWN}
-Move down and right (``southeast'') after insertion
-@*(@code{picture-movement-se}).
-@end table
-
-@kindex C-c C-f @r{(Picture mode)}
-@kindex C-c C-b @r{(Picture mode)}
-@findex picture-motion
-@findex picture-motion-reverse
- Two motion commands move based on the current Picture insertion
-direction. The command @kbd{C-c C-f} (@code{picture-motion}) moves in the
-same direction as motion after ``insertion'' currently does, while @kbd{C-c
-C-b} (@code{picture-motion-reverse}) moves in the opposite direction.
-
-@node Tabs in Picture
-@section Picture Mode Tabs
-
-@kindex M-TAB @r{(Picture mode)}
-@findex picture-tab-search
-@vindex picture-tab-chars
- Two kinds of tab-like action are provided in Picture mode. Use
-@kbd{M-@key{TAB}} (@code{picture-tab-search}) for context-based tabbing.
-With no argument, it moves to a point underneath the next
-``interesting'' character that follows whitespace in the previous
-nonblank line. ``Next'' here means ``appearing at a horizontal position
-greater than the one point starts out at.'' With an argument, as in
-@kbd{C-u M-@key{TAB}}, this command moves to the next such interesting
-character in the current line. @kbd{M-@key{TAB}} does not change the
-text; it only moves point. ``Interesting'' characters are defined by
-the variable @code{picture-tab-chars}, which should define a set of
-characters. The syntax for this variable is like the syntax used inside
-of @samp{[@dots{}]} in a regular expression---but without the @samp{[}
-and the @samp{]}. Its default value is @code{"!-~"}.
-
-@findex picture-tab
- @key{TAB} itself runs @code{picture-tab}, which operates based on the
-current tab stop settings; it is the Picture mode equivalent of
-@code{tab-to-tab-stop}. Normally it just moves point, but with a numeric
-argument it clears the text that it moves over.
-
-@kindex C-c TAB @r{(Picture mode)}
-@findex picture-set-tab-stops
- The context-based and tab-stop-based forms of tabbing are brought
-together by the command @kbd{C-c @key{TAB}} (@code{picture-set-tab-stops}).
-This command sets the tab stops to the positions which @kbd{M-@key{TAB}}
-would consider significant in the current line. The use of this command,
-together with @key{TAB}, can get the effect of context-based tabbing. But
-@kbd{M-@key{TAB}} is more convenient in the cases where it is sufficient.
-
- It may be convenient to prevent use of actual tab characters in
-pictures. For example, this prevents @kbd{C-x @key{TAB}} from messing
-up the picture. You can do this by setting the variable
-@code{indent-tabs-mode} to @code{nil}.
-
-@node Rectangles in Picture
-@section Picture Mode Rectangle Commands
-@cindex rectangles and Picture mode
-@cindex Picture mode and rectangles
-
- Picture mode defines commands for working on rectangular pieces of
-the text in ways that fit with the quarter-plane model. The standard
-rectangle commands may also be useful. @xref{Rectangles,,, emacs, the
-Emacs Manual}.
-
-@table @kbd
-@item C-c C-k
-Clear out the region-rectangle with spaces
-(@code{picture-clear-rectangle}). With argument, delete the text.
-@item C-c C-w @var{r}
-Similar, but save rectangle contents in register @var{r} first
-(@code{picture-clear-rectangle-to-register}).
-@item C-c C-y
-Copy last killed rectangle into the buffer by overwriting, with upper
-left corner at point (@code{picture-yank-rectangle}). With argument,
-insert instead.
-@item C-c C-x @var{r}
-Similar, but use the rectangle in register @var{r}
-(@code{picture-yank-rectangle-from-register}).
-@end table
-
-@kindex C-c C-k @r{(Picture mode)}
-@kindex C-c C-w @r{(Picture mode)}
-@findex picture-clear-rectangle
-@findex picture-clear-rectangle-to-register
- The picture rectangle commands @kbd{C-c C-k}
-(@code{picture-clear-rectangle}) and @kbd{C-c C-w}
-(@code{picture-clear-rectangle-to-register}) differ from the standard
-rectangle commands in that they normally clear the rectangle instead of
-deleting it; this is analogous with the way @kbd{C-d} is changed in Picture
-mode.
-
- However, deletion of rectangles can be useful in Picture mode, so
-these commands delete the rectangle if given a numeric argument.
-@kbd{C-c C-k} either with or without a numeric argument saves the
-rectangle for @kbd{C-c C-y}.
-
-@kindex C-c C-y @r{(Picture mode)}
-@kindex C-c C-x @r{(Picture mode)}
-@findex picture-yank-rectangle
-@findex picture-yank-rectangle-from-register
- The Picture mode commands for yanking rectangles differ from the
-standard ones in that they overwrite instead of inserting. This is
-the same way that Picture mode insertion of other text differs from
-other modes. @kbd{C-c C-y} (@code{picture-yank-rectangle}) inserts
-(by overwriting) the rectangle that was most recently killed, while
-@kbd{C-c C-x} (@code{picture-yank-rectangle-from-register}) does
-likewise for the rectangle found in a specified register.
-
-@node Advanced VC Usage
-@chapter Advanced VC Usage
-
- Commonly used features of Emacs' version control (VC) support are
-described in the main Emacs manual (@pxref{Version Control,,,emacs,
-the Emacs Manual}). This chapter describes more advanced VC usage.
-
-@menu
-* VC Dired Mode:: Listing files managed by version control.
-* VC Dired Commands:: Commands to use in a VC Dired buffer.
-* Remote Repositories:: Efficient access to remote CVS servers.
-* Snapshots:: Sets of file versions treated as a unit.
-* Miscellaneous VC:: Various other commands and features of VC.
-* Customizing VC:: Variables that change VC's behavior.
-@end menu
-
-@node VC Dired Mode
-@section Dired under VC
-
-@cindex PCL-CVS
-@pindex cvs
-@cindex CVS Dired Mode
- The VC Dired Mode described here works with all the version control
-systems that VC supports. Another more powerful facility, designed
-specifically for CVS, is called PCL-CVS. @xref{Top, , About PCL-CVS,
-pcl-cvs, PCL-CVS --- The Emacs Front-End to CVS}.
-
-@kindex C-x v d
-@findex vc-directory
- When you are working on a large program, it is often useful to find
-out which files have changed within an entire directory tree, or to view
-the status of all files under version control at once, and to perform
-version control operations on collections of files. You can use the
-command @kbd{C-x v d} (@code{vc-directory}) to make a directory listing
-that includes only files relevant for version control.
-
-@vindex vc-dired-terse-display
- @kbd{C-x v d} creates a buffer which uses VC Dired Mode. This looks
-much like an ordinary Dired buffer (@pxref{Dired,,,emacs, the
-Emacs Manual}); however, normally it shows only the noteworthy files
-(those locked or not up-to-date). This is called @dfn{terse display}.
-If you set the variable @code{vc-dired-terse-display} to @code{nil},
-then VC Dired shows all relevant files---those managed under version
-control, plus all subdirectories (@dfn{full display}). The command
-@kbd{v t} in a VC Dired buffer toggles between terse display and full
-display (@pxref{VC Dired Commands}).
-
-@vindex vc-dired-recurse
- By default, VC Dired produces a recursive listing of noteworthy or
-relevant files at or below the given directory. You can change this by
-setting the variable @code{vc-dired-recurse} to @code{nil}; then VC
-Dired shows only the files in the given directory.
-
- The line for an individual file shows the version control state in the
-place of the hard link count, owner, group, and size of the file. If
-the file is unmodified, in sync with the master file, the version
-control state shown is blank. Otherwise it consists of text in
-parentheses. Under RCS and SCCS, the name of the user locking the file
-is shown; under CVS, an abbreviated version of the @samp{cvs status}
-output is used. Here is an example using RCS:
-
-@smallexample
-@group
- /home/jim/project:
-
- -rw-r--r-- (jim) Apr 2 23:39 file1
- -r--r--r-- Apr 5 20:21 file2
-@end group
-@end smallexample
-
-@noindent
-The files @samp{file1} and @samp{file2} are under version control,
-@samp{file1} is locked by user jim, and @samp{file2} is unlocked.
-
- Here is an example using CVS:
-
-@smallexample
-@group
- /home/joe/develop:
-
- -rw-r--r-- (modified) Aug 2 1997 file1.c
- -rw-r--r-- Apr 4 20:09 file2.c
- -rw-r--r-- (merge) Sep 13 1996 file3.c
-@end group
-@end smallexample
-
- Here @samp{file1.c} is modified with respect to the repository, and
-@samp{file2.c} is not. @samp{file3.c} is modified, but other changes
-have also been checked in to the repository---you need to merge them
-with the work file before you can check it in.
-
-@vindex vc-stay-local
-@vindex vc-cvs-stay-local
- In the above, if the repository were on a remote machine, VC would
-only contact it when the variable @code{vc-stay-local} (or
-@code{vc-cvs-stay-local}) is nil (@pxref{CVS Options}). This is
-because access to the repository may be slow, or you may be working
-offline and not have access to the repository at all. As a
-consequence, VC would not be able to tell you that @samp{file3.c} is
-in the ``merge'' state; you would learn that only when you try to
-check-in your modified copy of the file, or use a command such as
-@kbd{C-x v m}.
-
- In practice, this is not a problem because CVS handles this case
-consistently whenever it arises. In VC, you'll simply get prompted to
-merge the remote changes into your work file first. The benefits of
-less network communication usually outweigh the disadvantage of not
-seeing remote changes immediately.
-
-@vindex vc-directory-exclusion-list
- When VC Dired displays subdirectories (in the ``full'' display mode),
-it omits some that should never contain any files under version control.
-By default, this includes Version Control subdirectories such as
-@samp{RCS} and @samp{CVS}; you can customize this by setting the
-variable @code{vc-directory-exclusion-list}.
-
- You can fine-tune VC Dired's format by typing @kbd{C-u C-x v d}---as in
-ordinary Dired, that allows you to specify additional switches for the
-@samp{ls} command.
-
-@node VC Dired Commands
-@section VC Dired Commands
-
- All the usual Dired commands work normally in VC Dired mode, except
-for @kbd{v}, which is redefined as the version control prefix. You can
-invoke VC commands such as @code{vc-diff} and @code{vc-print-log} by
-typing @kbd{v =}, or @kbd{v l}, and so on. Most of these commands apply
-to the file name on the current line.
-
- The command @kbd{v v} (@code{vc-next-action}) operates on all the
-marked files, so that you can lock or check in several files at once.
-If it operates on more than one file, it handles each file according to
-its current state; thus, it might lock one file, but check in another
-file. This could be confusing; it is up to you to avoid confusing
-behavior by marking a set of files that are in a similar state. If no
-files are marked, @kbd{v v} operates on the file in the current line.
-
- If any files call for check-in, @kbd{v v} reads a single log entry,
-then uses it for all the files being checked in. This is convenient for
-registering or checking in several files at once, as part of the same
-change.
-
-@findex vc-dired-toggle-terse-mode
-@findex vc-dired-mark-locked
- You can toggle between terse display (only locked files, or files not
-up-to-date) and full display at any time by typing @kbd{v t}
-(@code{vc-dired-toggle-terse-mode}). There is also a special command
-@kbd{* l} (@code{vc-dired-mark-locked}), which marks all files currently
-locked (or, with CVS, all files not up-to-date). Thus, typing @kbd{* l
-t k} is another way to delete from the buffer all files except those
-currently locked.
-
-@node Remote Repositories
-@section Remote Repositories
-@cindex remote repositories (CVS)
-
- A common way of using CVS is to set up a central CVS repository on
-some Internet host, then have each developer check out a personal
-working copy of the files on his local machine. Committing changes to
-the repository, and picking up changes from other users into one's own
-working area, then works by direct interactions with the CVS server.
-
- One difficulty is that access to the CVS server is often slow, and
-that developers might need to work off-line as well. VC is designed
-to reduce the amount of network interaction necessary.
-
-@menu
-* Version Backups:: Keeping local copies of repository versions.
-* Local Version Control:: Using another version system for local editing.
-@end menu
-
-@node Version Backups
-@subsection Version Backups
-@cindex version backups
-
-@cindex automatic version backups
- When VC sees that the CVS repository for a file is on a remote
-machine, it automatically makes local backups of unmodified versions
-of the file---@dfn{automatic version backups}. This means that you
-can compare the file to the repository version (@kbd{C-x v =}), or
-revert to that version (@kbd{C-x v u}), without any network
-interactions.
-
- The local copy of the unmodified file is called a @dfn{version
-backup} to indicate that it corresponds exactly to a version that is
-stored in the repository. Note that version backups are not the same
-as ordinary Emacs backup files (@pxref{Backup,,,emacs, the Emacs
-Manual}). But they follow a similar naming convention.
-
- For a file that comes from a remote CVS repository, VC makes a
-version backup whenever you save the first changes to the file, and
-removes it after you have committed your modified version to the
-repository. You can disable the making of automatic version backups by
-setting @code{vc-cvs-stay-local} to @code{nil} (@pxref{CVS Options}).
-
-@cindex manual version backups
- The name of the automatic version backup for version @var{version}
-of file @var{file} is @code{@var{file}.~@var{version}.~}. This is
-almost the same as the name used by @kbd{C-x v ~} (@pxref{Old
-Versions,,,emacs, the Emacs Manual}), the only difference being
-the additional dot (@samp{.}) after the version number. This
-similarity is intentional, because both kinds of files store the same
-kind of information. The file made by @kbd{C-x v ~} acts as a
-@dfn{manual version backup}.
-
- All the VC commands that operate on old versions of a file can use
-both kinds of version backups. For instance, @kbd{C-x v ~} uses
-either an automatic or a manual version backup, if possible, to get
-the contents of the version you request. Likewise, @kbd{C-x v =} and
-@kbd{C-x v u} use either an automatic or a manual version backup, if
-one of them exists, to get the contents of a version to compare or
-revert to. If you changed a file outside of Emacs, so that no
-automatic version backup was created for the previous text, you can
-create a manual backup of that version using @kbd{C-x v ~}, and thus
-obtain the benefit of the local copy for Emacs commands.
-
- The only difference in Emacs's handling of manual and automatic
-version backups, once they exist, is that Emacs deletes automatic
-version backups when you commit to the repository. By contrast,
-manual version backups remain until you delete them.
-
-@node Local Version Control
-@subsection Local Version Control
-@cindex local version control
-@cindex local back end (version control)
-
-When you make many changes to a file that comes from a remote
-repository, it can be convenient to have version control on your local
-machine as well. You can then record intermediate versions, revert to
-a previous state, etc., before you actually commit your changes to the
-remote server.
-
-VC lets you do this by putting a file under a second, local version
-control system, so that the file is effectively registered in two
-systems at the same time. For the description here, we will assume
-that the remote system is CVS, and you use RCS locally, although the
-mechanism works with any combination of version control systems
-(@dfn{back ends}).
-
-To make it work with other back ends, you must make sure that the
-``more local'' back end comes before the ``more remote'' back end in
-the setting of @code{vc-handled-backends} (@pxref{Customizing VC}). By
-default, this variable is set up so that you can use remote CVS and
-local RCS as described here.
-
-To start using local RCS for a file that comes from a remote CVS
-server, you must @emph{register the file in RCS}, by typing @kbd{C-u
-C-x v v rcs @key{RET}}. (In other words, use @code{vc-next-action} with a
-prefix argument, and specify RCS as the back end.)
-
-You can do this at any time; it does not matter whether you have
-already modified the file with respect to the version in the CVS
-repository. If possible, VC tries to make the RCS master start with
-the unmodified repository version, then checks in any local changes
-as a new version. This works if you have not made any changes yet, or
-if the unmodified repository version exists locally as a version
-backup (@pxref{Version Backups}). If the unmodified version is not
-available locally, the RCS master starts with the modified version;
-the only drawback to this is that you cannot compare your changes
-locally to what is stored in the repository.
-
-The version number of the RCS master is derived from the current CVS
-version, starting a branch from it. For example, if the current CVS
-version is 1.23, the local RCS branch will be 1.23.1. Version 1.23 in
-the RCS master will be identical to version 1.23 under CVS; your first
-changes are checked in as 1.23.1.1. (If the unmodified file is not
-available locally, VC will check in the modified file twice, both as
-1.23 and 1.23.1.1, to make the revision numbers consistent.)
-
-If you do not use locking under CVS (the default), locking is also
-disabled for RCS, so that editing under RCS works exactly as under
-CVS.
-
-When you are done with local editing, you can commit the final version
-back to the CVS repository by typing @kbd{C-u C-x v v cvs @key{RET}}.
-This initializes the log entry buffer (@pxref{Log Buffer,,,emacs, the
-Emacs Manual}) to contain all the log entries you have recorded in the
-RCS master; you can edit them as you wish, and then commit in CVS by
-typing @kbd{C-c C-c}. If the commit is successful, VC removes the RCS
-master, so that the file is once again registered under CVS only.
-(The RCS master is not actually deleted, just renamed by appending
-@samp{~} to the name, so that you can refer to it later if you wish.)
-
-While using local RCS, you can pick up recent changes from the CVS
-repository into your local file, or commit some of your changes back
-to CVS, without terminating local RCS version control. To do this,
-switch to the CVS back end temporarily, with the @kbd{C-x v b} command:
-
-@table @kbd
-@item C-x v b
-Switch to another back end that the current file is registered
-under (@code{vc-switch-backend}).
-
-@item C-u C-x v b @var{backend} @key{RET}
-Switch to @var{backend} for the current file.
-@end table
-
-@kindex C-x v b
-@findex vc-switch-backend
-@kbd{C-x v b} does not change the buffer contents, or any files; it
-only changes VC's perspective on how to handle the file. Any
-subsequent VC commands for that file will operate on the back end that
-is currently selected.
-
-If the current file is registered in more than one back end, typing
-@kbd{C-x v b} ``cycles'' through all of these back ends. With a
-prefix argument, it asks for the back end to use in the minibuffer.
-
-Thus, if you are using local RCS, and you want to pick up some recent
-changes in the file from remote CVS, first visit the file, then type
-@kbd{C-x v b} to switch to CVS, and finally use @kbd{C-x v m
-@key{RET}} to merge the news (@pxref{Merging,,,emacs, the Emacs
-Manual}). You can then switch back to RCS by typing @kbd{C-x v b}
-again, and continue to edit locally.
-
-But if you do this, the revision numbers in the RCS master no longer
-correspond to those of CVS. Technically, this is not a problem, but
-it can become difficult to keep track of what is in the CVS repository
-and what is not. So we suggest that you return from time to time to
-CVS-only operation, by committing your local changes back to the
-repository using @kbd{C-u C-x v v cvs @key{RET}}.
-
-@node Snapshots
-@section Snapshots
-@cindex snapshots and version control
-
- A @dfn{snapshot} is a named set of file versions (one for each
-registered file) that you can treat as a unit. One important kind of
-snapshot is a @dfn{release}, a (theoretically) stable version of the
-system that is ready for distribution to users.
-
-@menu
-* Making Snapshots:: The snapshot facilities.
-* Snapshot Caveats:: Things to be careful of when using snapshots.
-@end menu
-
-@node Making Snapshots
-@subsection Making and Using Snapshots
-
- There are two basic commands for snapshots; one makes a
-snapshot with a given name, the other retrieves a named snapshot.
-
-@table @code
-@kindex C-x v s
-@findex vc-create-snapshot
-@item C-x v s @var{name} @key{RET}
-Define the last saved versions of every registered file in or under the
-current directory as a snapshot named @var{name}
-(@code{vc-create-snapshot}).
-
-@kindex C-x v r
-@findex vc-retrieve-snapshot
-@item C-x v r @var{name} @key{RET}
-For all registered files at or below the current directory level, select
-whatever versions correspond to the snapshot @var{name}
-(@code{vc-retrieve-snapshot}).
-
-This command reports an error if any files are locked at or below the
-current directory, without changing anything; this is to avoid
-overwriting work in progress.
-@end table
-
- A snapshot uses a very small amount of resources---just enough to record
-the list of file names and which version belongs to the snapshot. Thus,
-you need not hesitate to create snapshots whenever they are useful.
-
- You can give a snapshot name as an argument to @kbd{C-x v =} or
-@kbd{C-x v ~} (@pxref{Old Versions,,,emacs, the Emacs Manual}).
-Thus, you can use it to compare a snapshot against the current files,
-or two snapshots against each other, or a snapshot against a named
-version.
-
-@node Snapshot Caveats
-@subsection Snapshot Caveats
-
-@cindex named configurations (RCS)
- VC's snapshot facilities are modeled on RCS's named-configuration
-support. They use RCS's native facilities for this, so
-snapshots made using RCS through VC are visible even when you bypass VC.
-
- With CVS, Meta-CVS, and Subversion, VC also uses the native
-mechanism provided by that back end to make snapshots and retrieve them
-(@dfn{tags} for CVS and Meta-CVS, @dfn{copies} for Subversion).
-
-@c worded verbosely to avoid overfull hbox.
- For SCCS, VC implements snapshots itself. The files it uses contain
-name/file/version-number triples. These snapshots are visible only
-through VC.
-
- There is no support for VC snapshots using GNU Arch yet.
-
- A snapshot is a set of checked-in versions. So make sure that all the
-files are checked in and not locked when you make a snapshot.
-
- File renaming and deletion can create some difficulties with snapshots.
-This is not a VC-specific problem, but a general design issue in version
-control systems that no one has solved very well yet.
-
- If you rename a registered file, you need to rename its master along
-with it (the command @code{vc-rename-file} does this automatically). If
-you are using SCCS, you must also update the records of the snapshot, to
-mention the file by its new name (@code{vc-rename-file} does this,
-too). An old snapshot that refers to a master file that no longer
-exists under the recorded name is invalid; VC can no longer retrieve
-it. It would be beyond the scope of this manual to explain enough about
-RCS and SCCS to explain how to update the snapshots by hand.
-
- Using @code{vc-rename-file} makes the snapshot remain valid for
-retrieval, but it does not solve all problems. For example, some of the
-files in your program probably refer to others by name. At the very
-least, the makefile probably mentions the file that you renamed. If you
-retrieve an old snapshot, the renamed file is retrieved under its new
-name, which is not the name that the makefile expects. So the program
-won't really work as retrieved.
-
-@node Miscellaneous VC
-@section Miscellaneous Commands and Features of VC
-
- This section explains the less-frequently-used features of VC.
-
-@menu
-* Change Logs and VC:: Generating a change log file from log entries.
-* Renaming and VC:: A command to rename both the source and master
- file correctly.
-* Version Headers:: Inserting version control headers into working files.
-@end menu
-
-@node Change Logs and VC
-@subsection Change Logs and VC
-
- If you use RCS or CVS for a program and also maintain a change log
-file for it (@pxref{Change Log,,,emacs, the Emacs Manual}), you
-can generate change log entries automatically from the version control
-log entries:
-
-@table @kbd
-@item C-x v a
-@kindex C-x v a
-@findex vc-update-change-log
-Visit the current directory's change log file and, for registered files
-in that directory, create new entries for versions checked in since the
-most recent entry in the change log file.
-(@code{vc-update-change-log}).
-
-This command works with RCS or CVS only, not with any of the other
-back ends.
-
-@item C-u C-x v a
-As above, but only find entries for the current buffer's file.
-
-@item M-1 C-x v a
-As above, but find entries for all the currently visited files that are
-maintained with version control. This works only with RCS, and it puts
-all entries in the log for the default directory, which may not be
-appropriate.
-@end table
-
- For example, suppose the first line of @file{ChangeLog} is dated
-1999-04-10, and that the only check-in since then was by Nathaniel
-Bowditch to @file{rcs2log} on 1999-05-22 with log text @samp{Ignore log
-messages that start with `#'.}. Then @kbd{C-x v a} visits
-@file{ChangeLog} and inserts text like this:
-
-@iftex
-@medbreak
+@lowersections
@end iftex
-@smallexample
-@group
-1999-05-22 Nathaniel Bowditch <nat@@apn.org>
-
- * rcs2log: Ignore log messages that start with `#'.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
-@noindent
-You can then edit the new change log entry further as you wish.
-
- Some of the new change log entries may duplicate what's already in
-ChangeLog. You will have to remove these duplicates by hand.
-
- Normally, the log entry for file @file{foo} is displayed as @samp{*
-foo: @var{text of log entry}}. The @samp{:} after @file{foo} is omitted
-if the text of the log entry starts with @w{@samp{(@var{functionname}):
-}}. For example, if the log entry for @file{vc.el} is
-@samp{(vc-do-command): Check call-process status.}, then the text in
-@file{ChangeLog} looks like this:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-05-06 Nathaniel Bowditch <nat@@apn.org>
-
- * vc.el (vc-do-command): Check call-process status.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
- When @kbd{C-x v a} adds several change log entries at once, it groups
-related log entries together if they all are checked in by the same
-author at nearly the same time. If the log entries for several such
-files all have the same text, it coalesces them into a single entry.
-For example, suppose the most recent check-ins have the following log
-entries:
-
-@flushleft
-@bullet{} For @file{vc.texinfo}: @samp{Fix expansion typos.}
-@bullet{} For @file{vc.el}: @samp{Don't call expand-file-name.}
-@bullet{} For @file{vc-hooks.el}: @samp{Don't call expand-file-name.}
-@end flushleft
-
-@noindent
-They appear like this in @file{ChangeLog}:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-04-01 Nathaniel Bowditch <nat@@apn.org>
-
- * vc.texinfo: Fix expansion typos.
-
- * vc.el, vc-hooks.el: Don't call expand-file-name.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
- Normally, @kbd{C-x v a} separates log entries by a blank line, but you
-can mark several related log entries to be clumped together (without an
-intervening blank line) by starting the text of each related log entry
-with a label of the form @w{@samp{@{@var{clumpname}@} }}. The label
-itself is not copied to @file{ChangeLog}. For example, suppose the log
-entries are:
-
-@flushleft
-@bullet{} For @file{vc.texinfo}: @samp{@{expand@} Fix expansion typos.}
-@bullet{} For @file{vc.el}: @samp{@{expand@} Don't call expand-file-name.}
-@bullet{} For @file{vc-hooks.el}: @samp{@{expand@} Don't call expand-file-name.}
-@end flushleft
-
-@noindent
-Then the text in @file{ChangeLog} looks like this:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-04-01 Nathaniel Bowditch <nat@@apn.org>
-
- * vc.texinfo: Fix expansion typos.
- * vc.el, vc-hooks.el: Don't call expand-file-name.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
- A log entry whose text begins with @samp{#} is not copied to
-@file{ChangeLog}. For example, if you merely fix some misspellings in
-comments, you can log the change with an entry beginning with @samp{#}
-to avoid putting such trivia into @file{ChangeLog}.
-
-@node Renaming and VC
-@subsection Renaming VC Work Files and Master Files
-
-@findex vc-rename-file
- When you rename a registered file, you must also rename its master
-file correspondingly to get proper results. Use @code{vc-rename-file}
-to rename the source file as you specify, and rename its master file
-accordingly. It also updates any snapshots (@pxref{Snapshots}) that
-mention the file, so that they use the new name; despite this, the
-snapshot thus modified may not completely work (@pxref{Snapshot
-Caveats}).
-
- Some back ends do not provide an explicit rename operation to their
-repositories. After issuing @code{vc-rename-file}, use @kbd{C-x v v}
-on the original and renamed buffers and provide the necessary edit
-log.
-
- You cannot use @code{vc-rename-file} on a file that is locked by
-someone else.
-
-@node Version Headers
-@subsection Inserting Version Control Headers
-
- Sometimes it is convenient to put version identification strings
-directly into working files. Certain special strings called
-@dfn{version headers} are replaced in each successive version by the
-number of that version, the name of the user who created it, and other
-relevant information. All of the back ends that VC supports have such
-a mechanism, except GNU Arch.
-
- VC does not normally use the information contained in these headers.
-The exception is RCS---with RCS, version headers are sometimes more
-reliable than the master file to determine which version of the file
-you are editing. Note that in a multi-branch environment, version
-headers are necessary to make VC behave correctly (@pxref{Multi-User
-Branching,,,emacs, the Emacs Manual}).
-
- Searching for RCS version headers is controlled by the variable
-@code{vc-consult-headers}. If it is non-@code{nil} (the default),
-Emacs searches for headers to determine the version number you are
-editing. Setting it to @code{nil} disables this feature.
-
- Note that although CVS uses the same kind of version headers as RCS
-does, VC never searches for these headers if you are using CVS,
-regardless of the above setting.
-
-@kindex C-x v h
-@findex vc-insert-headers
- You can use the @kbd{C-x v h} command (@code{vc-insert-headers}) to
-insert a suitable header string.
-
-@table @kbd
-@item C-x v h
-Insert headers in a file for use with your version-control system.
-@end table
-
-@vindex vc-@var{backend}-header
- The default header string is @samp{@w{$}Id$} for RCS and
-@samp{@w{%}W%} for SCCS. You can specify other headers to insert by
-setting the variables @code{vc-@var{backend}-header} where
-@var{backend} is @code{rcs} or @code{sccs}.
-
- Instead of a single string, you can specify a list of strings; then
-each string in the list is inserted as a separate header on a line of
-its own.
-
- It may be necessary to use apparently-superfluous backslashes when
-writing the strings that you put in this variable. For instance, you
-might write @code{"$Id\$"} rather than @code{"$Id@w{$}"}. The extra
-backslash prevents the string constant from being interpreted as a
-header, if the Emacs Lisp file containing it is maintained with
-version control.
-
-@vindex vc-comment-alist
- Each header is inserted surrounded by tabs, inside comment delimiters,
-on a new line at point. Normally the ordinary comment
-start and comment end strings of the current mode are used, but for
-certain modes, there are special comment delimiters for this purpose;
-the variable @code{vc-comment-alist} specifies them. Each element of
-this list has the form @code{(@var{mode} @var{starter} @var{ender})}.
-
-@vindex vc-static-header-alist
- The variable @code{vc-static-header-alist} specifies further strings
-to add based on the name of the buffer. Its value should be a list of
-elements of the form @code{(@var{regexp} . @var{format})}. Whenever
-@var{regexp} matches the buffer name, @var{format} is inserted as part
-of the header. A header line is inserted for each element that matches
-the buffer name, and for each string specified by
-@code{vc-@var{backend}-header}. The header line is made by processing the
-string from @code{vc-@var{backend}-header} with the format taken from the
-element. The default value for @code{vc-static-header-alist} is as follows:
-
-@example
-@group
-(("\\.c$" .
- "\n#ifndef lint\nstatic char vcid[] = \"\%s\";\n\
-#endif /* lint */\n"))
-@end group
-@end example
-
-@noindent
-It specifies insertion of text of this form:
-
-@example
-@group
-
-#ifndef lint
-static char vcid[] = "@var{string}";
-#endif /* lint */
-@end group
-@end example
-
-@noindent
-Note that the text above starts with a blank line.
-
- If you use more than one version header in a file, put them close
-together in the file. The mechanism in @code{revert-buffer} that
-preserves markers may not handle markers positioned between two version
-headers.
-
-@node Customizing VC
-@section Customizing VC
-
-@vindex vc-handled-backends
-The variable @code{vc-handled-backends} determines which version
-control systems VC should handle. The default value is @code{(RCS CVS
-SVN SCCS Arch MCVS)}, so it contains all six version systems that are
-currently supported. If you want VC to ignore one or more of these
-systems, exclude its name from the list. To disable VC entirely, set
-this variable to @code{nil}.
-
-The order of systems in the list is significant: when you visit a file
-registered in more than one system (@pxref{Local Version Control}), VC
-uses the system that comes first in @code{vc-handled-backends} by
-default. The order is also significant when you register a file for
-the first time, @pxref{Registering,,,emacs, the Emacs Manual} for
-details.
-
-@menu
-* General VC Options:: Options that apply to multiple back ends.
-* RCS and SCCS:: Options for RCS and SCCS.
-* CVS Options:: Options for CVS.
-@end menu
-
-@node General VC Options
-@subsection General Options
-
-@vindex vc-make-backup-files
- Emacs normally does not save backup files for source files that are
-maintained with version control. If you want to make backup files even
-for files that use version control, set the variable
-@code{vc-make-backup-files} to a non-@code{nil} value.
-
-@vindex vc-keep-workfiles
- Normally the work file exists all the time, whether it is locked or
-not. If you set @code{vc-keep-workfiles} to @code{nil}, then checking
-in a new version with @kbd{C-x v v} deletes the work file; but any
-attempt to visit the file with Emacs creates it again. (With CVS, work
-files are always kept.)
-
-@vindex vc-follow-symlinks
- Editing a version-controlled file through a symbolic link can be
-dangerous. It bypasses the version control system---you can edit the
-file without locking it, and fail to check your changes in. Also,
-your changes might overwrite those of another user. To protect against
-this, VC checks each symbolic link that you visit, to see if it points
-to a file under version control.
-
- The variable @code{vc-follow-symlinks} controls what to do when a
-symbolic link points to a version-controlled file. If it is @code{nil},
-VC only displays a warning message. If it is @code{t}, VC automatically
-follows the link, and visits the real file instead, telling you about
-this in the echo area. If the value is @code{ask} (the default), VC
-asks you each time whether to follow the link.
-
-@vindex vc-suppress-confirm
- If @code{vc-suppress-confirm} is non-@code{nil}, then @kbd{C-x v v}
-and @kbd{C-x v i} can save the current buffer without asking, and
-@kbd{C-x v u} also operates without asking for confirmation. (This
-variable does not affect @kbd{C-x v c}; that operation is so drastic
-that it should always ask for confirmation.)
-
-@vindex vc-command-messages
- VC mode does much of its work by running the shell commands for RCS,
-CVS and SCCS. If @code{vc-command-messages} is non-@code{nil}, VC
-displays messages to indicate which shell commands it runs, and
-additional messages when the commands finish.
-
-@vindex vc-path
- You can specify additional directories to search for version control
-programs by setting the variable @code{vc-path}. These directories
-are searched before the usual search path. It is rarely necessary to
-set this variable, because VC normally finds the proper files
-automatically.
-
-@node RCS and SCCS
-@subsection Options for RCS and SCCS
-
-@cindex non-strict locking (RCS)
-@cindex locking, non-strict (RCS)
- By default, RCS uses locking to coordinate the activities of several
-users, but there is a mode called @dfn{non-strict locking} in which
-you can check-in changes without locking the file first. Use
-@samp{rcs -U} to switch to non-strict locking for a particular file,
-see the @code{rcs} manual page for details.
-
- When deducing the version control state of an RCS file, VC first
-looks for an RCS version header string in the file (@pxref{Version
-Headers}). If there is no header string, VC normally looks at the
-file permissions of the work file; this is fast. But there might be
-situations when the file permissions cannot be trusted. In this case
-the master file has to be consulted, which is rather expensive. Also
-the master file can only tell you @emph{if} there's any lock on the
-file, but not whether your work file really contains that locked
-version.
-
-@vindex vc-consult-headers
- You can tell VC not to use version headers to determine the file
-status by setting @code{vc-consult-headers} to @code{nil}. VC then
-always uses the file permissions (if it is supposed to trust them), or
-else checks the master file.
-
-@vindex vc-mistrust-permissions
- You can specify the criterion for whether to trust the file
-permissions by setting the variable @code{vc-mistrust-permissions}.
-Its value can be @code{t} (always mistrust the file permissions and
-check the master file), @code{nil} (always trust the file
-permissions), or a function of one argument which makes the decision.
-The argument is the directory name of the @file{RCS} subdirectory. A
-non-@code{nil} value from the function says to mistrust the file
-permissions. If you find that the file permissions of work files are
-changed erroneously, set @code{vc-mistrust-permissions} to @code{t}.
-Then VC always checks the master file to determine the file's status.
-
- VC determines the version control state of files under SCCS much as
-with RCS. It does not consider SCCS version headers, though. Thus,
-the variable @code{vc-mistrust-permissions} affects SCCS use, but
-@code{vc-consult-headers} does not.
-
-@node CVS Options
-@subsection Options specific for CVS
-
-@cindex locking (CVS)
- By default, CVS does not use locking to coordinate the activities of
-several users; anyone can change a work file at any time. However,
-there are ways to restrict this, resulting in behavior that resembles
-locking.
-
-@cindex CVSREAD environment variable (CVS)
- For one thing, you can set the @env{CVSREAD} environment variable
-(the value you use makes no difference). If this variable is defined,
-CVS makes your work files read-only by default. In Emacs, you must
-type @kbd{C-x v v} to make the file writable, so that editing works
-in fact similar as if locking was used. Note however, that no actual
-locking is performed, so several users can make their files writable
-at the same time. When setting @env{CVSREAD} for the first time, make
-sure to check out all your modules anew, so that the file protections
-are set correctly.
-
-@cindex cvs watch feature
-@cindex watching files (CVS)
- Another way to achieve something similar to locking is to use the
-@dfn{watch} feature of CVS. If a file is being watched, CVS makes it
-read-only by default, and you must also use @kbd{C-x v v} in Emacs to
-make it writable. VC calls @code{cvs edit} to make the file writable,
-and CVS takes care to notify other developers of the fact that you
-intend to change the file. See the CVS documentation for details on
-using the watch feature.
-
-@vindex vc-stay-local
-@vindex vc-cvs-stay-local
-@cindex remote repositories (CVS)
- When a file's repository is on a remote machine, VC tries to keep
-network interactions to a minimum. This is controlled by the variable
-@code{vc-cvs-stay-local}. There is another variable,
-@code{vc-stay-local}, which enables the feature also for other back
-ends that support it, including CVS. In the following, we will talk
-only about @code{vc-cvs-stay-local}, but everything applies to
-@code{vc-stay-local} as well.
-
-If @code{vc-cvs-stay-local} is @code{t} (the default), then VC uses
-only the entry in the local CVS subdirectory to determine the file's
-state (and possibly information returned by previous CVS commands).
-One consequence of this is that when you have modified a file, and
-somebody else has already checked in other changes to the file, you
-are not notified of it until you actually try to commit. (But you can
-try to pick up any recent changes from the repository first, using
-@kbd{C-x v m @key{RET}}, @pxref{Merging,,,emacs, the Emacs Manual}).
-
- When @code{vc-cvs-stay-local} is @code{t}, VC also makes local
-version backups, so that simple diff and revert operations are
-completely local (@pxref{Version Backups}).
-
- On the other hand, if you set @code{vc-cvs-stay-local} to @code{nil},
-then VC queries the remote repository @emph{before} it decides what to
-do in @code{vc-next-action} (@kbd{C-x v v}), just as it does for local
-repositories. It also does not make any version backups.
-
- You can also set @code{vc-cvs-stay-local} to a regular expression
-that is matched against the repository host name; VC then stays local
-only for repositories from hosts that match the pattern.
-
-@vindex vc-cvs-global-switches
- You can specify additional command line options to pass to all CVS
-operations in the variable @code{vc-cvs-global-switches}. These
-switches are inserted immediately after the @code{cvs} command, before
-the name of the operation to invoke.
-
-
-@node Fortran
-@chapter Fortran Mode
-@cindex Fortran mode
-@cindex mode, Fortran
-
- Fortran mode provides special motion commands for Fortran statements
-and subprograms, and indentation commands that understand Fortran
-conventions of nesting, line numbers and continuation statements.
-Fortran mode has support for Auto Fill mode that breaks long lines into
-proper Fortran continuation lines.
-
- Special commands for comments are provided because Fortran comments
-are unlike those of other languages. Built-in abbrevs optionally save
-typing when you insert Fortran keywords.
-
- Use @kbd{M-x fortran-mode} to switch to this major mode. This
-command runs the hook @code{fortran-mode-hook}. @xref{Hooks,,, emacs,
-the Emacs Manual}.
-
-@cindex Fortran77 and Fortran90
-@findex f90-mode
-@findex fortran-mode
- Fortran mode is meant for editing Fortran77 ``fixed format'' (and also
-``tab format'') source code. For editing the modern Fortran90 or
-Fortran95 ``free format'' source code, use F90 mode (@code{f90-mode}).
-Emacs normally uses Fortran mode for files with extension @samp{.f},
-@samp{.F} or @samp{.for}, and F90 mode for the extension @samp{.f90} and
-@samp{.f95}. GNU Fortran supports both kinds of format.
-
-@menu
-* Motion: Fortran Motion. Moving point by statements or subprograms.
-* Indent: Fortran Indent. Indentation commands for Fortran.
-* Comments: Fortran Comments. Inserting and aligning comments.
-* Autofill: Fortran Autofill. Auto fill support for Fortran.
-* Columns: Fortran Columns. Measuring columns for valid Fortran.
-* Abbrev: Fortran Abbrev. Built-in abbrevs for Fortran keywords.
-@end menu
-
-@node Fortran Motion
-@section Motion Commands
-
- In addition to the normal commands for moving by and operating on
-``defuns'' (Fortran subprograms---functions and subroutines, as well as
-modules for F90 mode), Fortran mode provides special commands to move by
-statements and other program units.
-
-@table @kbd
-@kindex C-c C-n @r{(Fortran mode)}
-@findex fortran-next-statement
-@findex f90-next-statement
-@item C-c C-n
-Move to the beginning of the next statement
-(@code{fortran-next-statement}/@code{f90-next-statement}).
-
-@kindex C-c C-p @r{(Fortran mode)}
-@findex fortran-previous-statement
-@findex f90-previous-statement
-@item C-c C-p
-Move to the beginning of the previous statement
-(@code{fortran-previous-statement}/@code{f90-previous-statement}).
-If there is no previous statement (i.e. if called from the first
-statement in the buffer), move to the start of the buffer.
-
-@kindex C-c C-e @r{(F90 mode)}
-@findex f90-next-block
-@item C-c C-e
-Move point forward to the start of the next code block
-(@code{f90-next-block}). A code block is a subroutine,
-@code{if}--@code{endif} statement, and so forth. This command exists
-for F90 mode only, not Fortran mode. With a numeric argument, this
-moves forward that many blocks.
-
-@kindex C-c C-a @r{(F90 mode)}
-@findex f90-previous-block
-@item C-c C-a
-Move point backward to the previous code block
-(@code{f90-previous-block}). This is like @code{f90-next-block}, but
-moves backwards.
-
-@kindex C-M-n @r{(Fortran mode)}
-@findex fortran-end-of-block
-@findex f90-end-of-block
-@item C-M-n
-Move to the end of the current code block
-(@code{fortran-end-of-block}/@code{f90-end-of-block}). With a numeric
-agument, move forward that number of blocks. The mark is set before
-moving point. The F90 mode version of this command checks for
-consistency of block types and labels (if present), but it does not
-check the outermost block since that may be incomplete.
-
-@kindex C-M-p @r{(Fortran mode)}
-@findex fortran-beginning-of-block
-@findex f90-beginning-of-block
-@item C-M-p
-Move to the start of the current code block
-(@code{fortran-beginning-of-block}/@code{f90-beginning-of-block}). This
-is like @code{fortran-end-of-block}, but moves backwards.
-@end table
-
-@node Fortran Indent
-@section Fortran Indentation
-
- Special commands and features are needed for indenting Fortran code in
-order to make sure various syntactic entities (line numbers, comment line
-indicators and continuation line flags) appear in the columns that are
-required for standard, fixed (or tab) format Fortran.
-
-@menu
-* Commands: ForIndent Commands. Commands for indenting and filling Fortran.
-* Contline: ForIndent Cont. How continuation lines indent.
-* Numbers: ForIndent Num. How line numbers auto-indent.
-* Conv: ForIndent Conv. Conventions you must obey to avoid trouble.
-* Vars: ForIndent Vars. Variables controlling Fortran indent style.
-@end menu
-
-@node ForIndent Commands
-@subsection Fortran Indentation and Filling Commands
-
-@table @kbd
-@item C-M-j
-Break the current line at point and set up a continuation line
-(@code{fortran-split-line}).
-@item M-^
-Join this line to the previous line (@code{fortran-join-line}).
-@item C-M-q
-Indent all the lines of the subprogram point is in
-(@code{fortran-indent-subprogram}).
-@item M-q
-Fill a comment block or statement.
-@end table
-
-@kindex C-M-q @r{(Fortran mode)}
-@findex fortran-indent-subprogram
- The key @kbd{C-M-q} runs @code{fortran-indent-subprogram}, a command
-to reindent all the lines of the Fortran subprogram (function or
-subroutine) containing point.
-
-@kindex C-M-j @r{(Fortran mode)}
-@findex fortran-split-line
- The key @kbd{C-M-j} runs @code{fortran-split-line}, which splits
-a line in the appropriate fashion for Fortran. In a non-comment line,
-the second half becomes a continuation line and is indented
-accordingly. In a comment line, both halves become separate comment
-lines.
-
-@kindex M-^ @r{(Fortran mode)}
-@kindex C-c C-d @r{(Fortran mode)}
-@findex fortran-join-line
- @kbd{M-^} or @kbd{C-c C-d} runs the command @code{fortran-join-line},
-which joins a continuation line back to the previous line, roughly as
-the inverse of @code{fortran-split-line}. The point must be on a
-continuation line when this command is invoked.
-
-@kindex M-q @r{(Fortran mode)}
-@kbd{M-q} in Fortran mode fills the comment block or statement that
-point is in. This removes any excess statement continuations.
-
-@node ForIndent Cont
-@subsection Continuation Lines
-@cindex Fortran continuation lines
-
-@vindex fortran-continuation-string
- Most Fortran77 compilers allow two ways of writing continuation lines.
-If the first non-space character on a line is in column 5, then that
-line is a continuation of the previous line. We call this @dfn{fixed
-format}. (In GNU Emacs we always count columns from 0; but note that
-the Fortran standard counts from 1.) The variable
-@code{fortran-continuation-string} specifies what character to put in
-column 5. A line that starts with a tab character followed by any digit
-except @samp{0} is also a continuation line. We call this style of
-continuation @dfn{tab format}. (Fortran90 introduced ``free format'',
-with another style of continuation lines).
-
-@vindex indent-tabs-mode @r{(Fortran mode)}
-@vindex fortran-analyze-depth
-@vindex fortran-tab-mode-default
- Fortran mode can use either style of continuation line. When you
-enter Fortran mode, it tries to deduce the proper continuation style
-automatically from the buffer contents. It does this by scanning up to
-@code{fortran-analyze-depth} (default 100) lines from the start of the
-buffer. The first line that begins with either a tab character or six
-spaces determines the choice. If the scan fails (for example, if the
-buffer is new and therefore empty), the value of
-@code{fortran-tab-mode-default} (@code{nil} for fixed format, and
-non-@code{nil} for tab format) is used. @samp{/t} in the mode line
-indicates tab format is selected. Fortran mode sets the value of
-@code{indent-tabs-mode} accordingly.
-
- If the text on a line starts with the Fortran continuation marker
-@samp{$}, or if it begins with any non-whitespace character in column
-5, Fortran mode treats it as a continuation line. When you indent a
-continuation line with @key{TAB}, it converts the line to the current
-continuation style. When you split a Fortran statement with
-@kbd{C-M-j}, the continuation marker on the newline is created according
-to the continuation style.
-
- The setting of continuation style affects several other aspects of
-editing in Fortran mode. In fixed format mode, the minimum column
-number for the body of a statement is 6. Lines inside of Fortran
-blocks that are indented to larger column numbers always use only the
-space character for whitespace. In tab format mode, the minimum
-column number for the statement body is 8, and the whitespace before
-column 8 must always consist of one tab character.
-
-@node ForIndent Num
-@subsection Line Numbers
-
- If a number is the first non-whitespace in the line, Fortran
-indentation assumes it is a line number and moves it to columns 0
-through 4. (Columns always count from 0 in GNU Emacs.)
-
-@vindex fortran-line-number-indent
- Line numbers of four digits or less are normally indented one space.
-The variable @code{fortran-line-number-indent} controls this; it
-specifies the maximum indentation a line number can have. The default
-value of the variable is 1. Fortran mode tries to prevent line number
-digits passing column 4, reducing the indentation below the specified
-maximum if necessary. If @code{fortran-line-number-indent} has the
-value 5, line numbers are right-justified to end in column 4.
-
-@vindex fortran-electric-line-number
- Simply inserting a line number is enough to indent it according to
-these rules. As each digit is inserted, the indentation is recomputed.
-To turn off this feature, set the variable
-@code{fortran-electric-line-number} to @code{nil}.
-
-
-@node ForIndent Conv
-@subsection Syntactic Conventions
-
- Fortran mode assumes that you follow certain conventions that simplify
-the task of understanding a Fortran program well enough to indent it
-properly:
-
-@itemize @bullet
-@item
-Two nested @samp{do} loops never share a @samp{continue} statement.
-
-@item
-Fortran keywords such as @samp{if}, @samp{else}, @samp{then}, @samp{do}
-and others are written without embedded whitespace or line breaks.
-
-Fortran compilers generally ignore whitespace outside of string
-constants, but Fortran mode does not recognize these keywords if they
-are not contiguous. Constructs such as @samp{else if} or @samp{end do}
-are acceptable, but the second word should be on the same line as the
-first and not on a continuation line.
-@end itemize
-
-@noindent
-If you fail to follow these conventions, the indentation commands may
-indent some lines unaesthetically. However, a correct Fortran program
-retains its meaning when reindented even if the conventions are not
-followed.
-
-@node ForIndent Vars
-@subsection Variables for Fortran Indentation
-
-@vindex fortran-do-indent
-@vindex fortran-if-indent
-@vindex fortran-structure-indent
-@vindex fortran-continuation-indent
-@vindex fortran-check-all-num@dots{}
-@vindex fortran-minimum-statement-indent@dots{}
- Several additional variables control how Fortran indentation works:
-
-@table @code
-@item fortran-do-indent
-Extra indentation within each level of @samp{do} statement (default 3).
-
-@item fortran-if-indent
-Extra indentation within each level of @samp{if}, @samp{select case}, or
-@samp{where} statements (default 3).
-
-@item fortran-structure-indent
-Extra indentation within each level of @samp{structure}, @samp{union},
-@samp{map}, or @samp{interface} statements (default 3).
-
-@item fortran-continuation-indent
-Extra indentation for bodies of continuation lines (default 5).
-
-@item fortran-check-all-num-for-matching-do
-In Fortran77, a numbered @samp{do} statement is ended by any statement
-with a matching line number. It is common (but not compulsory) to use a
-@samp{continue} statement for this purpose. If this variable has a
-non-@code{nil} value, indenting any numbered statement must check for a
-@samp{do} that ends there. If you always end @samp{do} statements with
-a @samp{continue} line (or if you use the more modern @samp{enddo}),
-then you can speed up indentation by setting this variable to
-@code{nil}. The default is @code{nil}.
-
-@item fortran-blink-matching-if
-If this is @code{t}, indenting an @samp{endif} (or @samp{enddo}
-statement moves the cursor momentarily to the matching @samp{if} (or
-@samp{do}) statement to show where it is. The default is @code{nil}.
-
-@item fortran-minimum-statement-indent-fixed
-Minimum indentation for Fortran statements when using fixed format
-continuation line style. Statement bodies are never indented less than
-this much. The default is 6.
-
-@item fortran-minimum-statement-indent-tab
-Minimum indentation for Fortran statements for tab format continuation line
-style. Statement bodies are never indented less than this much. The
-default is 8.
-@end table
-
-The variables controlling the indentation of comments are described in
-the following section.
-
-@node Fortran Comments
-@section Fortran Comments
-
- The usual Emacs comment commands assume that a comment can follow a
-line of code. In Fortran77, the standard comment syntax requires an
-entire line to be just a comment. Therefore, Fortran mode replaces the
-standard Emacs comment commands and defines some new variables.
-
-@vindex fortran-comment-line-start
- Fortran mode can also handle the Fortran90 comment syntax where comments
-start with @samp{!} and can follow other text. Because only some Fortran77
-compilers accept this syntax, Fortran mode will not insert such comments
-unless you have said in advance to do so. To do this, set the variable
-@code{fortran-comment-line-start} to @samp{"!"}.
-
-@table @kbd
-@item M-;
-Align comment or insert new comment (@code{fortran-indent-comment}).
-
-@item C-x ;
-Applies to nonstandard @samp{!} comments only.
-
-@item C-c ;
-Turn all lines of the region into comments, or (with argument) turn them back
-into real code (@code{fortran-comment-region}).
-@end table
-
-@findex fortran-indent-comment
- @kbd{M-;} in Fortran mode is redefined as the command
-@code{fortran-indent-comment}. Like the usual @kbd{M-;} command, this
-recognizes any kind of existing comment and aligns its text appropriately;
-if there is no existing comment, a comment is inserted and aligned. But
-inserting and aligning comments are not the same in Fortran mode as in
-other modes.
-
- When a new comment must be inserted, if the current line is blank, a
-full-line comment is inserted. On a non-blank line, a nonstandard @samp{!}
-comment is inserted if you have said you want to use them. Otherwise a
-full-line comment is inserted on a new line before the current line.
-
- Nonstandard @samp{!} comments are aligned like comments in other
-languages, but full-line comments are different. In a standard full-line
-comment, the comment delimiter itself must always appear in column zero.
-What can be aligned is the text within the comment. You can choose from
-three styles of alignment by setting the variable
-@code{fortran-comment-indent-style} to one of these values:
-
-@vindex fortran-comment-indent-style
-@vindex fortran-comment-line-extra-indent
-@table @code
-@item fixed
-Align the text at a fixed column, which is the sum of
-@code{fortran-comment-line-extra-indent} and the minimum statement
-indentation. This is the default.
-
-The minimum statement indentation is
-@code{fortran-minimum-statement-indent-fixed} for fixed format
-continuation line style and @code{fortran-minimum-statement-indent-tab}
-for tab format style.
-
-@item relative
-Align the text as if it were a line of code, but with an additional
-@code{fortran-comment-line-extra-indent} columns of indentation.
-
-@item nil
-Don't move text in full-line comments automatically.
-@end table
-
-@vindex fortran-comment-indent-char
- In addition, you can specify the character to be used to indent within
-full-line comments by setting the variable
-@code{fortran-comment-indent-char} to the single-character string you want
-to use.
-
-@vindex fortran-directive-re
- Compiler directive lines, or preprocessor lines, have much the same
-appearance as comment lines. It is important, though, that such lines
-never be indented at all, no matter what the value of
-@code{fortran-comment-indent-style}. The variable
-@code{fortran-directive-re} is a regular expression that specifies which
-lines are directives. Matching lines are never indented, and receive
-distinctive font-locking.
-
- The normal Emacs comment command @kbd{C-x ;} has not been redefined. If
-you use @samp{!} comments, this command can be used with them. Otherwise
-it is useless in Fortran mode.
-
-@kindex C-c ; @r{(Fortran mode)}
-@findex fortran-comment-region
-@vindex fortran-comment-region
- The command @kbd{C-c ;} (@code{fortran-comment-region}) turns all the
-lines of the region into comments by inserting the string @samp{C$$$} at
-the front of each one. With a numeric argument, it turns the region
-back into live code by deleting @samp{C$$$} from the front of each line
-in it. The string used for these comments can be controlled by setting
-the variable @code{fortran-comment-region}. Note that here we have an
-example of a command and a variable with the same name; these two uses
-of the name never conflict because in Lisp and in Emacs it is always
-clear from the context which one is meant.
-
-@node Fortran Autofill
-@section Auto Fill in Fortran Mode
-
- Fortran mode has specialized support for Auto Fill mode, which is a
-minor mode that automatically splits statements as you insert them
-when they become too wide. Splitting a statement involves making
-continuation lines using @code{fortran-continuation-string}
-(@pxref{ForIndent Cont}). This splitting happens when you type
-@key{SPC}, @key{RET}, or @key{TAB}, and also in the Fortran
-indentation commands. You activate Auto Fill in Fortran mode in the
-normal way. @xref{Auto Fill,,, emacs, the Emacs Manual}.
-
-@vindex fortran-break-before-delimiters
- Auto Fill breaks lines at spaces or delimiters when the lines get
-longer than the desired width (the value of @code{fill-column}). The
-delimiters (besides whitespace) that Auto Fill can break at are
-@samp{+}, @samp{-}, @samp{/}, @samp{*}, @samp{=}, @samp{<}, @samp{>},
-and @samp{,}. The line break comes after the delimiter if the
-variable @code{fortran-break-before-delimiters} is @code{nil}.
-Otherwise (and by default), the break comes before the delimiter.
-
- To enable Auto Fill in all Fortran buffers, add
-@code{turn-on-auto-fill} to @code{fortran-mode-hook}. @xref{Hooks,,,
-emacs, the Emacs Manual}.
-
-@node Fortran Columns
-@section Checking Columns in Fortran
-
-@table @kbd
-@item C-c C-r
-Display a ``column ruler'' momentarily above the current line
-(@code{fortran-column-ruler}).
-@item C-c C-w
-Split the current window horizontally temporarily so that it is 72
-columns wide (@code{fortran-window-create-momentarily}). This may
-help you avoid making lines longer than the 72-character limit that
-some Fortran compilers impose.
-@item C-u C-c C-w
-Split the current window horizontally so that it is 72 columns wide
-(@code{fortran-window-create}). You can then continue editing.
-@item M-x fortran-strip-sequence-nos
-Delete all text in column 72 and beyond.
-@end table
-
-@kindex C-c C-r @r{(Fortran mode)}
-@findex fortran-column-ruler
- The command @kbd{C-c C-r} (@code{fortran-column-ruler}) shows a column
-ruler momentarily above the current line. The comment ruler is two lines
-of text that show you the locations of columns with special significance in
-Fortran programs. Square brackets show the limits of the columns for line
-numbers, and curly brackets show the limits of the columns for the
-statement body. Column numbers appear above them.
-
- Note that the column numbers count from zero, as always in GNU Emacs.
-As a result, the numbers may be one less than those you are familiar
-with; but the positions they indicate in the line are standard for
-Fortran.
-
-@vindex fortran-column-ruler-fixed
-@vindex fortran-column-ruler-tabs
- The text used to display the column ruler depends on the value of the
-variable @code{indent-tabs-mode}. If @code{indent-tabs-mode} is
-@code{nil}, then the value of the variable
-@code{fortran-column-ruler-fixed} is used as the column ruler.
-Otherwise, the value of the variable @code{fortran-column-ruler-tab} is
-displayed. By changing these variables, you can change the column ruler
-display.
-
-@kindex C-c C-w @r{(Fortran mode)}
-@findex fortran-window-create-momentarily
- @kbd{C-c C-w} (@code{fortran-window-create-momentarily}) temporarily
-splits the current window horizontally, making a window 72 columns
-wide, so you can see any lines that are too long. Type a space to
-restore the normal width.
-
-@kindex C-u C-c C-w @r{(Fortran mode)}
-@findex fortran-window-create
- You can also split the window horizontally and continue editing with
-the split in place. To do this, use @kbd{C-u C-c C-w} (@code{M-x
-fortran-window-create}). By editing in this window you can
-immediately see when you make a line too wide to be correct Fortran.
-
-@findex fortran-strip-sequence-nos
- The command @kbd{M-x fortran-strip-sequence-nos} deletes all text in
-column 72 and beyond, on all lines in the current buffer. This is the
-easiest way to get rid of old sequence numbers.
-
-@node Fortran Abbrev
-@section Fortran Keyword Abbrevs
-
- Fortran mode provides many built-in abbrevs for common keywords and
-declarations. These are the same sort of abbrev that you can define
-yourself. To use them, you must turn on Abbrev mode.
-@xref{Abbrevs,,, emacs, the Emacs Manual}.
-
- The built-in abbrevs are unusual in one way: they all start with a
-semicolon. You cannot normally use semicolon in an abbrev, but Fortran
-mode makes this possible by changing the syntax of semicolon to ``word
-constituent.''
-
- For example, one built-in Fortran abbrev is @samp{;c} for
-@samp{continue}. If you insert @samp{;c} and then insert a punctuation
-character such as a space or a newline, the @samp{;c} expands automatically
-to @samp{continue}, provided Abbrev mode is enabled.@refill
-
- Type @samp{;?} or @samp{;C-h} to display a list of all the built-in
-Fortran abbrevs and what they stand for.
-
-
-@node MS-DOS
-@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{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. Printing specifics 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
-
- 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 on MS-DOS 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.
-
-@xref{MS-Windows Printing,,,emacs, the Emacs Manual}, for details.
-
- 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}.
-
-@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.
-
-
-@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
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