If someone else has been working on the same files as you have, you may find that there are conflicting modifications. You'll discover this when you try to update your sources.
# cvs update
RCS file: LVM/tools/pvcreate.c,v
retrieving revision 1.5
retrieving revision 1.6
Merging differences between 1.5 and 1.6 into pvcreate.c
rcsmerge: warning: conflicts during merge
cvs server: conflicts found in tools/pvcreate.c
C tools/pvcreate.c
Don't panic! Your working file, as it existed before the update, is
saved under the filename .#pvcreate.c.1.5
.
You can always recover it should things go horribly wrong. The
file named `pvcreate.c' now contains
both the old (i.e. your) version
and new version of lines that conflicted. You simply edit the file
and resolve each conflict by deleting the unwanted version of the
lines involved.
<<<<<<< pvcreate.c j++; ======= j--; >>>>>>> 1.6
Don't forget to delete the lines with all the ``<'', ``='', and ``>'' symbols.