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(emacs)Version Headers

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Inserting Version Control Headers
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   Sometimes it is convenient to put version identification strings
directly into working files.  Certain special strings called "version
headers" are replaced in each successive version by the number of that
version.

   If you are using RCS, and version headers are present in your working
files, Emacs can use them to determine the current version and the
locking state of the files.  This is more reliable than referring to the
master files, which is done when there are no version headers.  Note
that in a multi-branch environment, version headers are necessary to
make VC behave correctly (Note: Multi-User Branching).

   Searching for version headers is controlled by the variable
`vc-consult-headers'.  If it is non-`nil' (the default), Emacs searches
for headers to determine the version number you are editing.  Setting
it to `nil' disables this feature.

   You can use the `C-x v h' command (`vc-insert-headers') to insert a
suitable header string.

`C-x v h'
     Insert headers in a file for use with your version-control system.

   The default header string is `$Id$' for RCS and `%W%' for SCCS.  You
can specify other headers to insert by setting the variable
`vc-header-alist'.  Its value is a list of elements of the form
`(PROGRAM . STRING)' where PROGRAM is `RCS' or `SCCS' and STRING is the
string to use.

   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 is often necessary to use "superfluous" backslashes when writing
the strings that you put in this variable.  For instance, you might
write `"$Id\$"' rather than `"$Id$"'.  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.

   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 `vc-comment-alist' specifies them.  Each element of this
list has the form `(MODE STARTER ENDER)'.

   The variable `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 `(REGEXP . FORMAT)'.  Whenever REGEXP matches the
buffer name, 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 `vc-header-alist'.  The header line is made by
processing the string from `vc-header-alist' with the format taken from
the element.  The default value for `vc-static-header-alist' is as
follows:

     (("\\.c$" .
       "\n#ifndef lint\nstatic char vcid[] = \"\%s\";\n\
     #endif /* lint */\n"))

It specifies insertion of text of this form:


     #ifndef lint
     static char vcid[] = "STRING";
     #endif /* lint */

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 `revert-buffer' that preserves
markers may not handle markers positioned between two version headers.