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From Henry Jen <henry...@ztune.net>
Subject Re: Patch for checking expat on Solaris
Date Mon, 01 May 2006 08:37:52 GMT
William A. Rowe, Jr. wrote:
> Henry Jen wrote:
>> William A. Rowe, Jr. wrote:
>>> The issue I have is that your -enforcing- -R destroys my 
>>> -portability-.  We
>>> need to find a happy comprimize to build to a manditory -prefix 
>>> versus the
>>> usual -prefix, yet relocatable (with LD_LIBRARY_PATH).
>> Hmm, I am curious what portability is destroyed. :-)

I misunderstood the portability you referring to, thought it means other
platforms. Glad to know that you are using Solaris and SunStudio. :-P

> IIUC, before patch, my solaris binary can deployed at an arbitrary 
> /opt/apache2/
> location, apachectl resolves the LD_LIBRARY_PATH.  Before patch, your 
> arbitrary
> solution (linked to a thirdparty build of expat installed in 
> /usr/local/lib or
> some other, nonstandard, location) fails to resolve libexpat.so at run 
> time.

-R gives a default search path, LIB_LIBRARY_PATH still can be used when

Quote `man ld.so.1` on Solaris:

      The runtime linker uses a prescribed search path for  locat-
      ing  the  dynamic  dependencies  of  an  object. The default
      search paths are the runpath recorded in  the  object,  fol-
      lowed  by  a  series  of  defaults.  For 32-bit objects, the
      defaults are /lib followed by /usr/lib. For 64-bit  objects,
      the  defaults  are  /lib/64  followed  by /usr/lib/64. These
      defaults component can be  modified  using  a  configuration
      file  that is created with crle(1). The runpath is specified
      when the dynamic object is constructed using the  -R  option
      to  ld(1).  The  environment variable LD_LIBRARY_PATH can be
      used to indicate  directories  to  be  searched  before  the
      default directories.

I work out the patch because I want to use the default expat installed
by Solaris system(in /usr/sfw/lib, which is not in the default search
path), not custom built or the one come with apr-util.

> After patch, my solaris binary can no longer be redeployed to 
> /opt/httpd/, but
> your binary finds your expat in /opt/sfw/lib or where ever.

This should not be true, but I could be overlooking. Would you please

The difference between with or without -R is the -R will be searched 
before the system default. Unless you got a different copy in the -R 
pointed path, there should be no difference. But I wonder how could that 
happen, -R is about to make sure you are getting the correct copy.

> So my point is, if you want to add -R explicitly to your ldflags, that's 
> cool.
> If you want to come up with a proposal to make this automatic but optional,
> that's cool too.  If you unilaterally decide your way is right, that's 
> not cool.

Your comment is very much appreciated, gives me a chance to exam my
understanding. :-)

Before we sort out the problem, how about let's remove the -R and commit
the rest? That at least allows configure to locate the lib correctly. I
will try to ping you on irc to have some discussion if you get some time.

As the coolness, I want to work with the community to make sure I am
doing the correct thing, which is why I always consult upstream team.
It's the advise I got from Solaris engineers to use -R instead of change
my system default setting with crle, and don't set LD_LIBRARY_PATH.
Following two URLs have covered the topic.


Thanks again for the comment, I really appreciate.


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