No subject

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When more than one person works on a software project things often get
complicated. Often, two people try to edit the same file simultaneously. One
solution, known as file locking or reserved checkouts, is to allow only one
person to edit each file at a time. This is the only solution with some version
control systems, including RCS and SCCS. Currently the usual way to get
reserved checkouts with CVS is the cvs admin -l command (see section A.6.1
admin options). This is not as nicely integrated into CVS as the watch features,
described below, but it seems that most people with a need for reserved
checkouts find it adequate. It also may be possible to use the watches features
described below, together with suitable procedures (not enforced by software),
to avoid having two people edit at the same time.
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There are statements at several points in that manual that files are normally
never locked.  So locking things is sort of contrary to their way of doing
things, which is a minor worry.