+++ /dev/null
-@c This is part of the Emacs manual.
-@c Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
-@c See file emacs.texi for copying conditions.
-@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).
-@node Remote Repositories
-@subsection Remote Repositories
-@cindex 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.
-
-@menu
-* Version Backups:: Keeping local copies of repository versions.
-* Local Version Control:: Using another version system for local editing.
-@end menu
-
-@node Version Backups
-@subsubsection Version Backups
-@cindex version backups
-
-@cindex 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 file---@dfn{automatic version backups}. This means that you
-can compare the file to the repository version (@kbd{C-x v =}), or
-revert to that version (@kbd{C-x v u}), without any network
-interactions.
-
- The local copy of the unmodified file is called a @dfn{version
-backup} to indicate that it corresponds exactly to a version that is
-stored in the repository. Note that version backups are not the same
-as ordinary Emacs backup files
-@iftex
-(@pxref{Backup,,,emacs, the Emacs Manual}).
-@end iftex
-@ifnottex
-(@pxref{Backup}).
-@end 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}).
-
-@cindex manual version backups
- The name of the automatic version backup for version @var{version}
-of file @var{file} is @code{@var{file}.~@var{version}.~}. This is
-almost the same as the name used by @kbd{C-x v ~}
-@iftex
-(@pxref{Old Revisions,,,emacs, the Emacs Manual}),
-@end iftex
-@ifnottex
-(@pxref{Old Revisions}),
-@end 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
-@kbd{C-x v u} use either an automatic or a manual version backup, if
-one of them exists, to get the contents of a version to compare or
-revert to. If you changed a file outside of Emacs, so that no
-automatic version backup was created for the previous text, you can
-create a manual backup of that version using @kbd{C-x v ~}, and thus
-obtain the benefit of the local copy for Emacs commands.
-
- The only difference in Emacs's handling of manual and automatic
-version backups, once they exist, is that Emacs deletes automatic
-version backups when you commit to the repository. By contrast,
-manual version backups remain until you delete them.
-
-@node Local Version Control
-@subsubsection Local Version Control
-@cindex local version control
-@cindex local back end (version control)
-
-When you make many changes to a file that comes from a remote
-repository, it can be convenient to have version control on your local
-machine as well. You can then record intermediate versions, revert to
-a previous state, etc., before you actually commit your changes to the
-remote server.
-
-VC lets you do this by putting a file under a second, local version
-control system, so that the file is effectively registered in two
-systems at the same time. For the description here, we will assume
-that the remote system is CVS, and you use RCS locally, although the
-mechanism works with any combination of version control systems
-(@dfn{back ends}).
-
-To make it work with other back ends, you must make sure that the
-``more local'' back end comes before the ``more remote'' back end in
-the setting of @code{vc-handled-backends} (@pxref{Customizing VC}). By
-default, this variable is set up so that you can use remote CVS and
-local RCS as described here.
-
-To start using local RCS for a file that comes from a remote CVS
-server, you must @emph{register the file in RCS}, by typing @kbd{C-u
-C-x v v rcs @key{RET}}. (In other words, use @code{vc-next-action} with a
-prefix argument, and specify RCS as the back end.)
-
-You can do this at any time; it does not matter whether you have
-already modified the file with respect to the version in the CVS
-repository. If possible, VC tries to make the RCS master start with
-the unmodified repository version, then checks in any local changes
-as a new version. This works if you have not made any changes yet, or
-if the unmodified repository version exists locally as a version
-backup (@pxref{Version Backups}). If the unmodified version is not
-available locally, the RCS master starts with the modified version;
-the only drawback to this is that you cannot compare your changes
-locally to what is stored in the repository.
-
-The version number of the RCS master is derived from the current CVS
-version, starting a branch from it. For example, if the current CVS
-version is 1.23, the local RCS branch will be 1.23.1. Version 1.23 in
-the RCS master will be identical to version 1.23 under CVS; your first
-changes are checked in as 1.23.1.1. (If the unmodified file is not
-available locally, VC will check in the modified file twice, both as
-1.23 and 1.23.1.1, to make the revision numbers consistent.)
-
-If you do not use locking under CVS (the default), locking is also
-disabled for RCS, so that editing under RCS works exactly as under
-CVS.
-
-When you are done with local editing, you can commit the final version
-back to the CVS repository by typing @kbd{C-u C-x v v cvs @key{RET}}.
-This initializes the log entry buffer
-@iftex
-(@pxref{Log Buffer,,,emacs, the Emacs Manual})
-@end iftex
-@ifnottex
-(@pxref{Log Buffer})
-@end 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
-@kbd{C-c C-c}. If the commit is successful, VC removes the RCS
-master, so that the file is once again registered under CVS only.
-(The RCS master is not actually deleted, just renamed by appending
-@samp{~} to the name, so that you can refer to it later if you wish.)
-
-While using local RCS, you can pick up recent changes from the CVS
-repository into your local file, or commit some of your changes back
-to CVS, without terminating local RCS version control. To do this,
-switch to the CVS back end temporarily, with the @kbd{C-x v b} command:
-
-@table @kbd
-@item C-x v b
-Switch to another back end that the current file is registered
-under (@code{vc-switch-backend}).
-
-@item C-u C-x v b @var{backend} @key{RET}
-Switch to @var{backend} for the current file.
-@end table
-
-@kindex C-x v b
-@findex vc-switch-backend
-@kbd{C-x v b} does not change the buffer contents, or any files; it
-only changes VC's perspective on how to handle the file. Any
-subsequent VC commands for that file will operate on the back end that
-is currently selected.
-
-If the current file is registered in more than one back end, typing
-@kbd{C-x v b} ``cycles'' through all of these back ends. With a
-prefix argument, it asks for the back end to use in the minibuffer.
-
-Thus, if you are using local RCS, and you want to pick up some recent
-changes in the file from remote CVS, first visit the file, then type
-@kbd{C-x v b} to switch to CVS, and finally use @kbd{C-x v m
-@key{RET}} to merge the news
-@iftex
-(@pxref{Merging,,,emacs, the Emacs Manual}).
-@end iftex
-@ifnottex
-(@pxref{Merging}).
-@end 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}}.
-
-@node Revision Tags
-@subsection Revision Tags
-@cindex tags and version control
-
- In a VCS with per-file revision numbers (such as SCCS, RCS, or CVS)
-@dfn{tag} 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.
-
-@menu
-* Making Revision Tags:: The tag facilities.
-* Revision Tag Caveats:: Things to be careful of when using tags.
-@end menu
-
-@node Making Revision Tags
-@subsubsection 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.
-
-@table @code
-@kindex C-x v s
-@findex vc-create-tag
-@item 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}).
-
-@kindex C-x v r
-@findex vc-retrieve-tag
-@item 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.
-@end 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
-@kbd{C-x v ~}
-@iftex
-(@pxref{Old Revisions,,,emacs, the Emacs Manual}).
-@end iftex
-@ifnottex
-(@pxref{Old Revisions}).
-@end ifnottex
-Thus, you can use it to compare a tagged version against the current files,
-or two tagged versions against each other.
-
-@node Revision Tag Caveats
-@subsubsection 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.
-
-@node Miscellaneous VC
-@subsection Miscellaneous Commands and Features of VC
-
- This section explains the less-frequently-used features of VC.
-
-@menu
-* Change Logs and VC:: Generating a change log file from log entries.
-* Renaming and VC:: A command to rename both the source and master
- file correctly.
-* Version Headers:: Inserting version control headers into working files.
-@end menu
-
-@node Change Logs and VC
-@subsubsection Change Logs and VC
-
- If you use RCS or CVS for a program and also maintain a change log
-file for it
-@iftex
-(@pxref{Change Log,,,emacs, the Emacs Manual}),
-@end iftex
-@ifnottex
-(@pxref{Change Log}),
-@end ifnottex
-you can generate change log entries automatically from the version
-control log entries:
-
-@table @kbd
-@item C-x v a
-@kindex C-x v a
-@findex vc-update-change-log
-Visit the current directory's change log file and, for registered files
-in that directory, create new entries for versions checked in since the
-most recent entry in the change log file.
-(@code{vc-update-change-log}).
-
-This command works with RCS or CVS only, not with any of the other
-back ends.
-
-@item C-u C-x v a
-As above, but only find entries for the current buffer's file.
-
-@item M-1 C-x v a
-As above, but find entries for all the currently visited files that are
-maintained with version control. This works only with RCS, and it puts
-all entries in the log for the default directory, which may not be
-appropriate.
-@end table
-
- For example, suppose the first line of @file{ChangeLog} is dated
-1999-04-10, and that the only check-in since then was by Nathaniel
-Bowditch to @file{rcs2log} on 1999-05-22 with log text @samp{Ignore log
-messages that start with `#'.}. Then @kbd{C-x v a} visits
-@file{ChangeLog} and inserts text like this:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-05-22 Nathaniel Bowditch <nat@@apn.org>
-
- * rcs2log: Ignore log messages that start with `#'.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
-@noindent
-You can then edit the new change log entry further as you wish.
-
- Some of the new change log entries may duplicate what's already in
-ChangeLog. You will have to remove these duplicates by hand.
-
- Normally, the log entry for file @file{foo} is displayed as @samp{*
-foo: @var{text of log entry}}. The @samp{:} after @file{foo} is omitted
-if the text of the log entry starts with @w{@samp{(@var{functionname}):
-}}. For example, if the log entry for @file{vc.el} is
-@samp{(vc-do-command): Check call-process status.}, then the text in
-@file{ChangeLog} looks like this:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-05-06 Nathaniel Bowditch <nat@@apn.org>
-
- * vc.el (vc-do-command): Check call-process status.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
- When @kbd{C-x v a} adds several change log entries at once, it groups
-related log entries together if they all are checked in by the same
-author at nearly the same time. If the log entries for several such
-files all have the same text, it coalesces them into a single entry.
-For example, suppose the most recent check-ins have the following log
-entries:
-
-@flushleft
-@bullet{} For @file{vc.texinfo}: @samp{Fix expansion typos.}
-@bullet{} For @file{vc.el}: @samp{Don't call expand-file-name.}
-@bullet{} For @file{vc-hooks.el}: @samp{Don't call expand-file-name.}
-@end flushleft
-
-@noindent
-They appear like this in @file{ChangeLog}:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-04-01 Nathaniel Bowditch <nat@@apn.org>
-
- * vc.texinfo: Fix expansion typos.
-
- * vc.el, vc-hooks.el: Don't call expand-file-name.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
- Normally, @kbd{C-x v a} separates log entries by a blank line, but you
-can mark several related log entries to be clumped together (without an
-intervening blank line) by starting the text of each related log entry
-with a label of the form @w{@samp{@{@var{clumpname}@} }}. The label
-itself is not copied to @file{ChangeLog}. For example, suppose the log
-entries are:
-
-@flushleft
-@bullet{} For @file{vc.texinfo}: @samp{@{expand@} Fix expansion typos.}
-@bullet{} For @file{vc.el}: @samp{@{expand@} Don't call expand-file-name.}
-@bullet{} For @file{vc-hooks.el}: @samp{@{expand@} Don't call expand-file-name.}
-@end flushleft
-
-@noindent
-Then the text in @file{ChangeLog} looks like this:
-
-@iftex
-@medbreak
-@end iftex
-@smallexample
-@group
-1999-04-01 Nathaniel Bowditch <nat@@apn.org>
-
- * vc.texinfo: Fix expansion typos.
- * vc.el, vc-hooks.el: Don't call expand-file-name.
-@end group
-@end smallexample
-@iftex
-@medbreak
-@end iftex
-
- A log entry whose text begins with @samp{#} is not copied to
-@file{ChangeLog}. For example, if you merely fix some misspellings in
-comments, you can log the change with an entry beginning with @samp{#}
-to avoid putting such trivia into @file{ChangeLog}.
-
-@node Renaming and VC
-@subsubsection 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 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.
-
-@node Version Headers
-@subsubsection 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
-@iftex
-(@pxref{Multi-User Branching,,,emacs, the Emacs Manual}).
-@end iftex
-@ifnottex
-(@pxref{Multi-User Branching}).
-@end ifnottex
-
- 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
-@subsection 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 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
-@iftex
-@ref{Registering,,,emacs, the Emacs Manual},
-@end iftex
-@ifnottex
-@ref{Registering},
-@end ifnottex
-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
-@subsubsection 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
-@subsubsection 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
-@subsubsection 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}},
-@iftex
-@pxref{Merging,,,emacs, the Emacs Manual}).
-@end iftex
-@ifnottex
-@pxref{Merging}).
-@end 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.
-
-@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.
-
-@ignore
- arch-tag: 140b8629-4339-4b5e-9e50-72453e51615e
-@end ignore
projects / emacs.git / commitdiff