Renaming a shared library in the port-framework to match FreeBSD naming schemes?

[Andrew W. Nosenko]

On Fri, Nov 19, 2010 at 19:28, O. Hartmann
<ohartman at mail.zedat.fu-berlin.de> wrote:
> On 11/19/10 18:11, Andrew W. Nosenko wrote:
>>
>> 2010/11/19 O. Hartmann<ohartman at zedat.fu-berlin.de>:
>>>
>>> On 11/19/10 13:46, Koop Mast wrote:
>>>>
>>>> On Fri, 19 Nov 2010 12:32:33 +0100
>>>> "O. Hartmann"<ohartman at zedat.fu-berlin.de>    wrote:
>>>>
>>>>> Hello.
>>>>> Trying to do my first port and run into trouble.
>>>>> The software package (Xerces-c 3.1.1) comes with a full autotoll
>>>>> environment and so far building and installing works.
>>>>>
>>>>> But the libarary name is "libxerces-c-3.1.so" and I need to change this
>>>>> to respect the FreeBSD nameing schemes to "libxerces-c.so.31". I'm
>>>>> looking for a way avoiding some "post-install:" stuff.
>>>>
>>>> There isn't any problem with the libxerces-c-3.1.so name.
>>>>  From http://www.freebsd.org/doc/en/books/porters-handbook/special.html
>>>> Try to keep shared library version numbers in the libfoo.so.0 format.
>>>> Our runtime linker only cares for the major (first) number.
>>>
>>> Well, this is the problem. The automated installation process installes
>>> libxerces-c-3.1.so.
>>
>> This not a problem.  Inability to catch the libxerces-c-3.1.so by
>> specifying -lxerces-c linker flag (and enforce you to specify
>> -lxerces-c-3.1) is intended and desired effect.  Please, don't touch
>> the library name.
>>
>> Usually, authors change library name if want to ensure and express
>> complete API and ABI break without any forward and backward
>> compatibility.  Like switch from Glib-1.x (libglib.so.x) to Glib-2.x
>> (libglib-2.0.so.x).  In both your (libxerces) and my (libglib)
>> examples the authors desired to use "interface generation" numbers,
>> but it just for aesthetics reasons, indeed the libraries could be
>> renamed to any other arbitrary way (for example, libNewGlib.so and
>> libEvenBetterXerces.so -- ideologically and technically there no
>> differences).
>>
>> If you rename libxerces-c-3.1.so to libxerces-c.so.31, then all
>> application that want and expect the old "zero-generation" API and
>> link against '-llibxerces-c' will fail because will catch absolutely
>> unexpected (by them) and incompatible libxerces-c-3.1 API.
>>
>> Applications that indeed want and expect libxerces-c-3.1 API, and
>> therefore that links with '-llibxerces-c-3.1' will fail also.  Just
>> because there no more libxerces-c-3.1.so library -- it was renamed to
>> unexpected name w/o good reasons.
>>
>> Conclusion: Please, don't touch library names!
>>
>
> Well, maybe here is a misunderstanding.

Sure.  See below.

> I'd like to come along with FreeBSD's library naming scheme when installing
> the library into /usr/local/lib. I thought manipulating the
> source-environment when compiling would be the least-efford way, but I see,
> maybe it would be easier to come along with a post-install: target by simply
> moving and making a symbolic link. If so, I need to detect by the framework
> what the lib vendor has choosen as thi lib name, to automate the proceed
> perfectly. Is this possible?
>

Seems, like you think that Xerces authors use libNAME-VER.so naming
scheme, while FreeBSD uses libNAME.so.VER ...

Ineed it's simple not true.  Both uses libNAME.so[.VER].
Usually, libNAME.so.VER with greatest VER symlinked to libNAME.so.
How VER represented (it just a number, or more complicated like .N,
.N.M., .N.M.K... -- depends on the ld.so implementation on the target
system and usually should not bother you as software author (if you
use Libtool, which is good in job of hiding differences between
systems in that respect).

Also, these .N[.M[.K]] represent the ABI version of library and has
nothing with package version.

Just in the case of Xerces, the NAME contains digits that looks like
version (version of package).  But indeed, the NAME in your case _is_
"libxerces-c-3.1".  I unable to say what ABI version VER is without
building Xerces-C, or upstream authors decided to left it empty
indeed, sorry.

-- 
Andrew W. Nosenko <andrew.w.nosenko at gmail.com>