-@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}.
-