@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.
-
- 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.
+ On Subversion, CVS, RCS, and SCCS, you can put certain special
+strings called @dfn{version headers} into a work file. When the file
+is committed, the version control system automatically puts the
+revision number, the name of the user who made the commit, and other
+relevant information into the version header.
+
+@vindex vc-consult-headers
+ VC does not normally use the information in the version headers. As
+an exception, when using RCS, Emacs uses the version header, if there
+is one, to determine the file version, since it is often more reliable
+than the RCS master file. To inhibit using the version header this
+way, change the variable @code{vc-consult-headers} to @code{nil}.
@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{$}"}. The extra
-backslash prevents the string constant from being interpreted as a
-header, if the Emacs Lisp file containing it is maintained with
-version control.
-
-@vindex vc-comment-alist
- Each header is inserted surrounded by tabs, inside comment delimiters,
-on a new line at point. Normally the ordinary comment
-start and comment end strings of the current mode are used, but for
-certain modes, there are special comment delimiters for this purpose;
-the variable @code{vc-comment-alist} specifies them. Each element of
-this list has the form @code{(@var{mode} @var{starter} @var{ender})}.
+ To insert a suitable header string into the current buffer, type
+@kbd{C-x v h} (@code{vc-insert-headers}). This command works only on
+Subversion, CVS, RCS, and SCCS. The variable
+@code{vc-@var{backend}-header} contains the list of keywords to insert
+into the version header; for instance, CVS uses @code{vc-cvs-header},
+whose default value is @code{'("\$Id\$")}. (The extra backslashes
+prevent the string constant from being interpreted as a header, if the
+Emacs Lisp file defining it is maintained with version control.) The
+@kbd{C-x v h} command inserts each keyword in the list on a new line
+at point, surrounded by tabs, and inside comment delimiters if
+necessary.
@vindex vc-static-header-alist
The variable @code{vc-static-header-alist} specifies further strings
to add based on the name of the buffer. Its value should be a list of
elements of the form @code{(@var{regexp} . @var{format})}. Whenever
-@var{regexp} matches the buffer name, @var{format} is inserted as part
-of the header. A header line is inserted for each element that matches
-the buffer name, and for each string specified by
-@code{vc-@var{backend}-header}. The header line is made by processing the
-string from @code{vc-@var{backend}-header} with the format taken from the
-element. The default value for @code{vc-static-header-alist} is as follows:
-
-@example
-@group
-(("\\.c$" .
- "\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.
+@var{regexp} matches the buffer name, @var{format} is also inserted as
+part of the version header. A @samp{%s} in @var{format} is replaced
+with the file's version control type.
@node Customizing VC
@subsection Customizing VC
@vindex vc-handled-backends
-The variable @code{vc-handled-backends} determines which version
+ 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 Mtn 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}.
+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, VC uses the system that comes
+ The order of systems in the list is significant: when you visit a
+file registered in more than one system, 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
+significant when you register a file for the first time
@iftex
-@ref{Registering,,,emacs, the Emacs Manual},
+(@pxref{Registering,,,emacs, the Emacs Manual}).
@end iftex
@ifnottex
-@ref{Registering},
+(@pxref{Registering}).
@end ifnottex
-for details.
@menu
* General VC Options:: Options that apply to multiple back ends.
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.
+@cindex symbolic links (and version control)
+ Editing a version-controlled file through a symbolic link may cause
+unexpected results, if you are unaware that the underlying file is
+version-controlled. The variable @code{vc-follow-symlinks} controls
+what Emacs does if you try to visit a symbolic link pointing to a
+version-controlled file. If the value is @code{ask} (the default),
+Emacs asks for confirmation. If it is @code{nil}, Emacs just displays
+a warning message. If it is @code{t}, Emacs automatically follows the
+link and visits the real file instead.
@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.)
+@kbd{C-x v u} also operates without asking for confirmation.
@vindex vc-command-messages
VC mode does much of its work by running the shell commands for the
-appropriate backend. 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.
+appropriate version control system. 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
projects / emacs.git / commitdiff