When your version control system is merging-based (the default for CVS and all newer version control systems), work files are always writable; you need not do anything special to begin editing a file. The status indicator on the mode line is ‘-’ if the file is unmodified; it flips to ‘:’ as soon as you save any changes (see VC Mode Line).
Here is what C-x v v does when using a merging-based system:
To pick up any recent changes from the repository without trying to commit your own changes, type C-x v m <RET>. See Merging.
These rules also apply when you use RCS in its “non-locking” mode, except that changes are not automatically merged from the repository. Nothing informs you if another user has committed changes in the same file since you began editing it; when you commit your revision, his changes are removed (however, they remain in the repository and are thus not irrevocably lost). Therefore, you must verify that the current revision is unchanged before checking in your changes. In addition, locking is possible with RCS even in this mode: C-x v v with an unmodified file locks the file, just as it does with RCS in its normal locking mode (see VC With A Locking VCS).blog comments powered by Disqus