ediff: Support for Version Control

 
 7.10 Support for Version Control
 ================================
 
 Ediff supports version control and lets you compare versions of files
 visited by Emacs buffers via the function ‘ediff-revision’.  This
 feature is controlled by the following variables:
 
 ‘ediff-version-control-package’
      A symbol.  The default is ‘vc’.
 
      If you are like most Emacs users, Ediff will use VC as the version
      control package.  This is the standard Emacs interface to RCS, CVS,
      and SCCS.
 
      However, if your needs are better served by other interfaces, you
      will have to tell Ediff which version control package you are
      using, e.g.,
           (setq ediff-version-control-package 'rcs)
 
      Apart from the standard ‘vc.el’, Ediff supports three other
      interfaces to version control: ‘rcs.el’, ‘pcl-cvs.el’ (recently
      renamed pcvs.el), and ‘generic-sc.el’.  The package ‘rcs.el’ is
      written by Sebastian Kremer <sk@thp.Uni-Koeln.DE> and is available
      as
           ftp.cs.buffalo.edu:pub/Emacs/rcs.tar.Z
           ftp.uni-koeln.de:/pub/gnu/emacs/rcs.tar.Z
 
    Ediff’s interface to the above packages allows the user to compare
 the versions of the current buffer or to merge them (with or without an
 ancestor-version).  These operations can also be performed on
 directories containing files under version control.
 
    In case of ‘pcl-cvs.el’, Ediff can also be invoked via the function
 ‘run-ediff-from-cvs-buffer’—see the documentation string for this
 function.