[csw-maintainers] An idea for a shared libraries policy

Philip Brown phil at bolthole.com
Thu Oct 7 15:55:44 CEST 2010

On Wed, Oct 6, 2010 at 9:42 PM, Maciej (Matchek) Blizinski
<maciej at opencsw.org> wrote:
> (Phil wrote)
>> I think you might do well to go with my original theory, slightly expanded:
>> Unless you find a shared object, of filename "lib*.so*", AND it has a
>> "SONAME", AND that name has a double-numeric rev  (eg:
>> libfoo.so.#.#), then you should just leave it alone.
> I understand and I agree with the first two criteria: It makes sense
> to separate the library out, if it is named lib*.so*, and has a
> SONAME.  I don't get the bit with the double-numeric versions.  What
> matters is the presence of SONAME, and the contents is a conventional
> notation, why would any numbers matter?

(I did explain this previously, but I'll repeat myself for this case)
It has been my experience that libraries with only a single digit
signifier in the SONAME, tend to respect backward compatibility, and
the value of a stable API.
They tend to not ever change the SONAME, unless the major version of
the associated program changes. in which case, there's no reason to
split out the shared lib even more, if it was not normally done so.
(note that I do explicitly mean the SONAME. if just the filename has
double digits, that doesnt count)

In contrast, developers who put in the minor rev number to the SONAME,
are practically announcing the fact of, "We have no respect for
consistency across major version numbers. We are specifically
intending to introduce incompatible features in minor revisions of the
Hence why they have gone to the extra trouble of putting in the minor
rev number into the SONAME.

summary: single-digit SONAME implies long term stability. double digit
SONAME implies frequent change, and thus a very good reason to split
out the lib for dependancy purposes.

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