[Emacs-diffs] Changes to emacs/doc/emacs/vc1-xtra.texi,v

[Chong Yidong]

CVSROOT:        /sources/emacs
Module name:    emacs
Changes by:     Chong Yidong <cyd>      08/10/21 20:50:27

Index: vc1-xtra.texi
===================================================================
RCS file: /sources/emacs/emacs/doc/emacs/vc1-xtra.texi,v
retrieving revision 1.11
retrieving revision 1.12
diff -u -b -r1.11 -r1.12
--- vc1-xtra.texi       6 Aug 2008 18:59:19 -0000       1.11
+++ vc1-xtra.texi       21 Oct 2008 20:50:27 -0000      1.12
@@ -4,164 +4,788 @@
 @c
 @c This file is included either in vc-xtra.texi (when producing the
 @c printed version) or in the main Emacs manual (for the on-line version).
address@hidden VC Directory Mode
address@hidden VC Directory Mode
 
address@hidden PCL-CVS
address@hidden cvs
address@hidden CVS directory mode
-  The VC directory 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}.
-
address@hidden C-x v d
address@hidden vc-dir
-  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-dir}) to make a directory listing
-that includes only files relevant for version control.
-
-  @kbd{C-x v d} creates a buffer which uses VC directory mode.  This
-buffer will contain a listing of version-controlled files below the
-current directory, and their containing directories.  Files which are
-up-to-date (have no local differences from the repository copy) will be
-omitted; if all files in a directory are up-to-date, the directory will
-be omitted as well.  (However, the directory in which @code{vc-dir} was
-run will always be shown as @file{./}.)  There is an exception to this
-rule: if VC mode detects that a file changed to up-to-date state since
-you last looked at it, that state will be shown.
-
-  If a directory uses more that one VC system, you can select which VC
-system to use for the @code{vc-dir} command by invoking @code{vc-dir}
-with a prefix argument, i.e.@: @kbd{C-u C-x v d}.
-
-  The line for an individual file will show the version control state of
-the file.  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:
address@hidden Remote Repositories
address@hidden Remote Repositories
address@hidden remote repositories
+
+  A common way of using CVS and other more advanced VCSes is to set up
+a central 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 repository server.
+
+  One difficulty is that access to a repository server is often slow,
+and that developers might need to work off-line as well.  While only
+third-generation decentralized VCses such as GNU Arch or Mercurial
+really solve this problem, VC is designed to reduce the amount of
+network interaction necessary.
+
+  If you are using a truly decentralized VCS you can skip the rest of
+this section. It describes backup and local-repository techniques
+that are only useful for Subversion and earlier VCSes.
+
address@hidden
+* Version Backups::        Keeping local copies of repository versions.
+* Local Version Control::  Using another version system for local editing.
address@hidden menu
+
address@hidden Version Backups
address@hidden Version Backups
address@hidden version backups
+
address@hidden automatic version backups
+  When VC sees that the repository for a file is on a remote
+machine, it automatically makes local backups of unmodified versions
+of the address@hidden 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
address@hidden
+(@pxref{Backup,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Backup}).
address@hidden ifnottex
+But they follow a similar naming convention.
+
+  For a file that comes from a remote 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}).
+
address@hidden manual version backups
+  The name of the automatic version backup for version @var{version}
+of file @var{file} is @address@hidden@var{version}.~}.  This is
+almost the same as the name used by @kbd{C-x v ~}
address@hidden
+(@pxref{Old Revisions,,,emacs, the Emacs Manual}),
address@hidden iftex
address@hidden
+(@pxref{Old Revisions}),
address@hidden ifnottex
+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
address@hidden 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.
+
address@hidden Local Version Control
address@hidden Local Version Control
address@hidden local version control
address@hidden 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
address@hidden
+(@pxref{Log Buffer,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Log Buffer})
address@hidden ifnottex
+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
address@hidden 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
address@hidden 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:
+
address@hidden @kbd
address@hidden C-x v b
+Switch to another back end that the current file is registered
+under (@code{vc-switch-backend}).
+
address@hidden C-u C-x v b @var{backend} @key{RET}
+Switch to @var{backend} for the current file.
address@hidden table
+
address@hidden C-x v b
address@hidden vc-switch-backend
address@hidden 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
address@hidden 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
address@hidden v b} to switch to CVS, and finally use @kbd{C-x v m
address@hidden to merge the news
address@hidden
+(@pxref{Merging,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Merging}).
address@hidden ifnottex
+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}}.
+
address@hidden Revision Tags
address@hidden Revision Tags
address@hidden tags and version control
+
+  In a VCS with per-file revision numbers (such as SCCS, RCS, or CVS)
address@hidden is a named set of file versions (one for each registered
+file) that you can treat as a unit.  In a VCS with per-repository
+version numbers (Subversion and most later ones) a tag is simply
+a symbolic name for a revsion.
+
+   One important kind of tag is a @dfn{release}, a (theoretically)
+stable version of the system that is ready for distribution to users.
+
address@hidden
+* Making Revision Tags::               The tag facilities.
+* Revision Tag Caveats::               Things to be careful of when using tags.
address@hidden menu
+
address@hidden Making Revision Tags
address@hidden Making and Using Revision Tags
+
+  There are two basic commands for tags; one makes a
+tag with a given name, the other retrieves a named tag.
+
address@hidden @code
address@hidden C-x v s
address@hidden vc-create-tag
address@hidden C-x v s @var{name} @key{RET}
+Define the working revision of every registered file in or under the
+current directory as a tag named @var{name}
+(@code{vc-create-tag}).
+
address@hidden C-x v r
address@hidden vc-retrieve-tag
address@hidden C-x v r @var{name} @key{RET}
+For all registered files at or below the current directory level,
+retrieve the tagged revision @var{name}. This command will 
+switch to a branch if @var{name} is a branch name and your VCS
+distinguishes branches from tags. 
+(@code{vc-retrieve-tag}).
+
+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.
address@hidden table
+
+Tags are inexpensive, so you need not hesitate to create them whenever
+they are useful.  Branches vary in cost depending on your VCS; in
+older ones they may be expensive.
+
+  You can give a tag or branch name as an argument to @kbd{C-x v =} or
address@hidden v ~}
address@hidden
+(@pxref{Old Revisions,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Old Revisions}).
address@hidden ifnottex
+Thus, you can use it to compare a tagged version against the current files,
+or two tagged versions against each other.
+
address@hidden Revision Tag Caveats
address@hidden Revision Tag Caveats
+
+  For SCCS, VC implements tags itself; these tags are visible only
+through VC.  Most later systems (including CVS, Subversion, bzr, git,
+and hg) have a native tag facility, and VC uses it where
+available; those tags will be visible even when you bypass VC.
+
+  There is no support for VC tags using GNU Arch yet.
+
+  Under older VCSes (SCCS, RCS, CVS, early versions of Subversion),
+renaming and deletion could create some difficulties with tags.  This is
+not a VC-specific problem, but a general design issue in version
+control systems that was not solved effectively until the earliest
+third-generation systems.
+
+  In a file-oriented VCS, when you rename a registered file you need
+to rename its master along with it; the command @code{vc-rename-file}
+will do this automatically.  If you are using SCCS, you must also
+update the records of the tag, to mention the file by its new name
+(@code{vc-rename-file} does this, too).  An old tag 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 tags by hand.
+
+  Using @code{vc-rename-file} makes the tag 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 tag, 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.
+
address@hidden Miscellaneous VC
address@hidden Miscellaneous Commands and Features of VC
+
+  This section explains the less-frequently-used features of VC.
+
address@hidden
+* 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.
address@hidden menu
+
address@hidden Change Logs and VC
address@hidden Change Logs and VC
+
+  If you use RCS or CVS for a program and also maintain a change log
+file for it
address@hidden
+(@pxref{Change Log,,,emacs, the Emacs Manual}),
address@hidden iftex
address@hidden
+(@pxref{Change Log}),
address@hidden ifnottex
+you can generate change log entries automatically from the version
+control log entries:
+
address@hidden @kbd
address@hidden C-x v a
address@hidden C-x v a
address@hidden 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.
+
address@hidden C-u C-x v a
+As above, but only find entries for the current buffer's file.
+
address@hidden 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.
address@hidden 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
address@hidden and inserts text like this:
+
address@hidden
address@hidden
address@hidden iftex
address@hidden
address@hidden
+1999-05-22  Nathaniel Bowditch  <nat@@apn.org>
+
+        * rcs2log: Ignore log messages that start with `#'.
address@hidden group
address@hidden smallexample
address@hidden
address@hidden
address@hidden iftex
+
address@hidden
+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 @address@hidden(@var{functionname}):
+}}.  For example, if the log entry for @file{vc.el} is
address@hidden(vc-do-command): Check call-process status.}, then the text in
address@hidden looks like this:
+
address@hidden
address@hidden
address@hidden iftex
address@hidden
address@hidden
+1999-05-06  Nathaniel Bowditch  <nat@@apn.org>
+
+        * vc.el (vc-do-command): Check call-process status.
address@hidden group
address@hidden smallexample
address@hidden
address@hidden
address@hidden 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:
+
address@hidden
address@hidden For @file{vc.texinfo}: @samp{Fix expansion typos.}
address@hidden For @file{vc.el}: @samp{Don't call expand-file-name.}
address@hidden For @file{vc-hooks.el}: @samp{Don't call expand-file-name.}
address@hidden flushleft
+
address@hidden
+They appear like this in @file{ChangeLog}:
+
address@hidden
address@hidden
address@hidden iftex
address@hidden
address@hidden
+1999-04-01  Nathaniel Bowditch  <nat@@apn.org>
 
-  Here is an example using CVS:
+        * vc.texinfo: Fix expansion typos.
 
+        * vc.el, vc-hooks.el: Don't call expand-file-name.
address@hidden group
address@hidden smallexample
address@hidden
address@hidden
address@hidden 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 @address@hidden@address@hidden@} }}.  The label
+itself is not copied to @file{ChangeLog}.  For example, suppose the log
+entries are:
+
address@hidden
address@hidden For @file{vc.texinfo}: @address@hidden@} Fix expansion typos.}
address@hidden For @file{vc.el}: @address@hidden@} Don't call expand-file-name.}
address@hidden For @file{vc-hooks.el}: @address@hidden@} Don't call 
expand-file-name.}
address@hidden flushleft
+
address@hidden
+Then the text in @file{ChangeLog} looks like this:
+
address@hidden
address@hidden
address@hidden iftex
 @smallexample
 @group
-                       ./
-    modified           file1.c
-    needs-update       file2.c
-    needs-merge        file3.c
+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
address@hidden
address@hidden
address@hidden iftex
+
+  A log entry whose text begins with @samp{#} is not copied to
address@hidden  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}.
+
address@hidden Renaming and VC
address@hidden Renaming VC Work Files and Master Files
+
address@hidden 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 tags (@pxref{Revision Tags}) that
+mention the file, so that they use the new name; despite this, the
+tag thus modified may not completely work (@pxref{Revision Tag 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.
+
address@hidden Version Headers
address@hidden Inserting Version Control Headers
+
+   Sometimes it is convenient to put version identification strings
+directly into working files.  Certain special strings called
address@hidden 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
address@hidden
+(@pxref{Multi-User Branching,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Multi-User Branching}).
address@hidden ifnottex
+
+  Searching for RCS version headers is controlled by the variable
address@hidden  If it is address@hidden (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.
+
address@hidden C-x v h
address@hidden vc-insert-headers
+  You can use the @kbd{C-x v h} command (@code{vc-insert-headers}) to
+insert a suitable header string.
+
address@hidden @kbd
address@hidden C-x v h
+Insert headers in a file for use with your version-control system.
address@hidden table
+
address@hidden address@hidden
+  The default header string is @address@hidden for RCS and
address@hidden@w{%}W%} for SCCS.  You can specify other headers to insert by
+setting the variables @address@hidden where
address@hidden 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{"$Id\$"} rather than @code{"address@hidden"}.  The extra
+backslash prevents the string constant from being interpreted as a
+header, if the Emacs Lisp file containing it is maintained with
+version control.
+
address@hidden vc-comment-alist
+  Each header is inserted surrounded by tabs, inside comment delimiters,
+on a new line at point.  Normally the ordinary comment
+start and comment end strings of the current mode are used, but for
+certain modes, there are special comment delimiters for this purpose;
+the variable @code{vc-comment-alist} specifies them.  Each element of
+this list has the form @code{(@var{mode} @var{starter} @var{ender})}.
+
address@hidden vc-static-header-alist
+  The variable @code{vc-static-header-alist} specifies further strings
+to add based on the name of the buffer.  Its value should be a list of
+elements of the form @code{(@var{regexp} . @var{format})}.  Whenever
address@hidden matches the buffer name, @var{format} is inserted as part
+of the header.  A header line is inserted for each element that matches
+the buffer name, and for each string specified by
address@hidden@var{backend}-header}.  The header line is made by processing the
+string from @address@hidden with the format taken from the
+element.  The default value for @code{vc-static-header-alist} is as follows:
+
address@hidden
address@hidden
+(("\\.c$" .
+  "\n#ifndef lint\nstatic char vcid[] = \"\%s\";\n\
+#endif /* lint */\n"))
address@hidden group
address@hidden example
+
address@hidden
+It specifies insertion of text of this form:
+
address@hidden
address@hidden
+
+#ifndef lint
+static char vcid[] = "@var{string}";
+#endif /* lint */
address@hidden group
address@hidden example
+
address@hidden
+Note that the text above starts with a blank line.
 
-  Here @samp{file1.c} is modified with respect to the repository, and
address@hidden 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.
+  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.
+
address@hidden Customizing VC
address@hidden Customizing VC
+
address@hidden 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 BZR GIT HG Arch)}, so it contains all the 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, see
address@hidden
address@hidden,,,emacs, the Emacs Manual},
address@hidden iftex
address@hidden
address@hidden,
address@hidden ifnottex
+for details.
+
address@hidden
+* General VC Options::  Options that apply to multiple back ends.
+* RCS and SCCS::        Options for RCS and SCCS.
+* CVS Options::         Options for CVS.
address@hidden menu
+
address@hidden General VC Options
address@hidden General Options
+
address@hidden 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
address@hidden to a address@hidden value.
+
address@hidden 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.)
+
address@hidden 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.
+
address@hidden vc-suppress-confirm
+  If @code{vc-suppress-confirm} is address@hidden, then @kbd{C-x v v}
+and @kbd{C-x v i} can save the current buffer without asking, and
address@hidden 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.)
+
address@hidden 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 address@hidden, VC
+displays messages to indicate which shell commands it runs, and
+additional messages when the commands finish.
+
address@hidden 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.
+
address@hidden RCS and SCCS
address@hidden Options for RCS and SCCS
+
address@hidden non-strict locking (RCS)
address@hidden 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
address@hidden -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.
+
address@hidden 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.
+
address@hidden 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
address@hidden 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
address@hidden does not.
+
address@hidden CVS Options
address@hidden Options specific for CVS
+
address@hidden 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.
+
address@hidden 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.
+
address@hidden cvs watch feature
address@hidden watching files (CVS)
+  Another way to achieve something similar to locking is to use the
address@hidden 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
-  In the above, if the repository were on a remote machine, VC would
-only contact it when the variable @code{vc-stay-local} (or
address@hidden) 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
address@hidden 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.
-
address@hidden vc-directory-exclusion-list
-  When a VC directory displays subdirectories it omits some that
-should never contain any files under version control.  By default,
-this includes Version Control subdirectories such as @samp{RCS} and
address@hidden; you can customize this by setting the variable
address@hidden
-
address@hidden VC Directory Commands
address@hidden VC Directory Commands
-
-  VC Directory mode has a full set of navigation and marking commands
-for picking out filesets.  Some of these are also available in a
-context menu invoked by the @kbd{mouse-2} button.
-
-  Up- and down-arrow keys move in the buffer; @kbd{n} and @kbd{p}  also
-move vertically as in other list-browsing modes.  @key{SPC} and
address@hidden behave like down-arrow, and @key{BackTab} behaves like
-up-arrow.
-
-  Both @kbd{C-m} and @kbd{f} visit the file on the current
-line.  @kbd{o} visits that file in another window.  @kbd{q} dismisses
-the directory buffer.
-
-  @kbd{x} toggles hiding of up-to-date files.
-  
-  @kbd{m} marks the file or directory on the current line.  If the
-region is active, @kbd{m} marks all the files in the region.  There
-are some restrictions when marking: a file cannot be marked if any of
-its parent directories are marked, and a directory cannot be marked if
-any files in it or in its child directories are marked.
-
-  @kbd{M} marks all the files with the same VC state as the current
-file if the cursor is on a file.  If the cursor is on a directory, it
-marks all child files.  With a prefix argument: marks all files and
-directories.
-
-  @kbd{u} unmarks the file or directory on the current line.  If the
-region is active, it unmarks all the files in the region.
-
-  @kbd{U} marks all the files with the same VC state as the current file
-if the cursor is on a file.  If the cursor is on a directory, it
-unmarks all child files.  With a prefix argument: unmarks all marked
-files and directories.
-
-  It is possible to do search, search and replace, incremental search,
-and incremental regexp search on multiple files.  These commands will
-work on all the marked files or the current file if nothing is marked.
-If a directory is marked, the files in that directory shown in the VC
-directory buffer will be used.
-
-  @kbd{S} searches the marked files.
-
-  @kbd{Q} does a query replace on the marked files.
-
-  @kbd{M-s a C-s} does an incremental search on the marked files.
-
-  @kbd{M-s a C-M-s} does an incremental search on the marked files.
-
-  Commands are also accessible from the VC-dir menu.  Note that some VC
-backends use the VC-dir menu to make available extra backend specific
-commands.
-
-  Normal VC commands with the @kbd{C-x v} prefix work in VC directory
-buffers.  Some single-key shortcuts are available as well; @kbd{=},
address@hidden, @kbd{l}, @kbd{i}, and @kbd{v} behave as through prefixed with
address@hidden v}.
-
-  The command @kbd{C-x v v} (@code{vc-next-action}) operates on all the
-marked files, so that you can check in several files at once.
-If the underlying VC supports atomic commits of multiple-file
-changesets, @kbd{C-x v v} with a selected set of modified but not
-committed files will commit all of them at once as a single changeset.
-
-  When @kbd{C-x v v} (@code{vc-next-action}) operates on a set of files,
-it requires that all of those files must be either in the same state or
-in compatible states; otherwise it will throw an error (added,
-modified and removed states are considered compatible).  Note that this
-differs from the behavior of older versions of VC, which did not have
-fileset operations and simply did @code{vc-next-action} on each file
-individually.
-
-  If any files are in a state that calls for commit, @kbd{C-x v v} reads a
-single log entry and uses it for the changeset as a whole.  If the
-underling VCS is file- rather than changeset-oriented, the log entry
-will be replicated into the history of each file.
address@hidden 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
address@hidden  There is another variable,
address@hidden, 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
address@hidden 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
address@hidden v m @key{RET}},
address@hidden
address@hidden,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
address@hidden).
address@hidden ifnottex
+
+  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.
+
address@hidden 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.
 
 @ignore
    arch-tag: 8e8c2a01-ad41-4e61-a89a-60131ad67263