23.8.3.1 Basic Version Control with Locking

If locking is used for the file (as with SCCS, and RCS in its default mode), C-x v v can either lock a file or check it in:

• If the file is not locked, C-x v v locks it, and makes it writable so that you can change it.
• If the file is locked by you, and contains changes, C-x v v checks in the changes. In order to do this, it first reads the log entry for the new version. See section Features of the Log Entry Buffer.
• If the file is locked by you, but you have not changed it since you locked it, C-x v v releases the lock and makes the file read-only again.
• If the file is locked by some other user, C-x v v asks you whether you want to “steal the lock” from that user. If you say yes, the file becomes locked by you, but a message is sent to the person who had formerly locked the file, to inform him of what has happened.

These rules also apply when you use CVS in locking mode, except that there is no such thing as stealing a lock.