Thread

1. Shared libs with version numbers.

   Darren King <darrenk@insightdist.com> — 1998-04-29T19:50:21Z

   Silly question since I work with aix and it doesn't appear to use
   the version numbers for shared libs...
   
   Is there any purpose to the version numbers that some ports append
   to a shared lib name, besides keeping different versions around?
   
   I've managed to move the port specific code from all of the various
   interfaces that make shared libs, but I'd like to understand the
   rhyme/reason before I post a patch that breaks all other ports.
   
   Using libpq as an example, is there a difference to the system if...
   
   $(MAKE) libpq.so
   $(INSTALL) libpq.so libpq.so.1
   $(LN) libpq.so.1 libpq.so
   
   ...rather than...
   
   $(MAKE) libpq.so.1
   $(INSTALL) libpq.so.1 libpq.so.1
   $(LN) libpq.so.1 libpq.so
   
   ???
   
   If no difference to the system, the former is _much_ easier to add
   shared lib support for aix and use the %.$(DLSUFFIX) rules in the
   port Makefiles.
   
   This would be perhaps the final step to removing $(PORTNAME) from the
   code, these Makefiles would not have to be generated by configure, and
   makes the interfaces/* Makefiles much cleaner.
   
   darrenk
   
   

2. Re: [HACKERS] Shared libs with version numbers.

   Michael Meskes <meskes@topsystem.de> — 1998-04-30T07:25:02Z

   Darren King writes:
   > Is there any purpose to the version numbers that some ports append
   > to a shared lib name, besides keeping different versions around?
   
   Yes. Making sure your application doesn't load an incompatible version of
   the lib.
   
   > Using libpq as an example, is there a difference to the system if...
   > 
   > $(MAKE) libpq.so
   > $(INSTALL) libpq.so libpq.so.1
   > $(LN) libpq.so.1 libpq.so
   > 
   > ...rather than...
   > 
   > $(MAKE) libpq.so.1
   > $(INSTALL) libpq.so.1 libpq.so.1
   > $(LN) libpq.so.1 libpq.so
   
   No. The file the system knows is libpq.so.1 either way. You might even call
   it foo.bar in your Makefile as long as it is installed as libpq.so.1.
   
   Michael
   
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3. Re: [HACKERS] Shared libs with version numbers.

   Tom Ivar Helbekkmo <tih+mail@hamartun.priv.no> — 1998-04-30T07:41:10Z

   darrenk@insightdist.com (Darren King) writes:
   
   > Is there any purpose to the version numbers that some ports append
   > to a shared lib name, besides keeping different versions around?
   
   Well, no.  That _is_ the point.  Sort of.  Version numbers make it
   possible to have different generations of shared libraries installed,
   and have different binaries use different ones.  You can then install
   a new version of the library -- and nothing will use it.  Once you
   recompile some binary, though, it will henceforth dynamically link
   against the new one, i.e. the one that it was built for.  This is, of
   course, important because it allows the interface to change when the
   version changes, without forcing you to recompile _everything_.
   
   -tih
   -- 
   Popularity is the hallmark of mediocrity.  --Niles Crane, "Frasier"