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From Justin Erenkrantz <>
Subject Re: Problem compiling mod_webapp for IBM HTTP Server 1.9.19 running on AIX 4.3.3. Please help save Tomcat for a high profile project in Switzerland
Date Sun, 18 Nov 2001 18:34:42 GMT
On Sat, Nov 17, 2001 at 08:51:24PM +0100, wrote:
> First of all I attempt to calmly summarize the problem and only then let my emotions
get through. 
> My insufficient knowledge of AIX platforms prevents me from successfully compiling mod_webapp
(as well mod_jk) on AIX 4.3.3 platform.
> Tomcat itself appears to be running flawlessly. Unfortunately due to my meager knowledge
of AIX I seem to be unable to recompile neither mod_webapp nor mod_jk for the specified platform.
Actually compilation worked fine in both cases. What did fail was the ‘ld’ linker. As far
as I can judge about possible cause of failure, the linker requires a module export (.exp)
file in order to be able successfully complete linking process. In this respect AIX appears
to differ from Unixes, as I had no problems at all building mod_webapp & mod_jk under
Linux (Mandrake 8.0 & Mandrake 8.1) as well as Solaris 8. The problem is aggravated by
the management’s desire to use IBM HTTP Server instead of plain Apache mainly due to IBM’s
SSL support, which is perceived to be more trustworthy and secure. 
> Is my assumption right? If yes, is there a way I could generate that damn .exp file for
mod_webapp? I could also live with mod_jk as a fallback scenario. 
> Please help.

My hypothesis here is that your biggest obstacle is your OS not your 
knowledge of it.  I wish there was a better answer, but you can't 
easily build custom complex DSOs in AIX.  (Switching OSes doesn't
seem like an option since you have IBM hardware.)

AIUI, the problem here is due to the AIX linker and how it handles
dependencies (that .exp file - it isn't hard to generate it, but the
linker doesn't know what to do with it anyway).  I have a feeling 
that it may stop mod_webapp from working as a DSO since it requires 

I know that Aaron Bannert spent some time working with the IBM
httpd folks (Victor, Greg, Bill, Jeff, etc.) trying to get AIX DSO 
support for Apache 2.0 and APR.  I believe the eventual conclusion 
from the IBM AIX gurus in Austin was that the linker is not capable 
of handling external dependencies in an acceptable manner.  Their
recommendation was to wait for the next major release of AIX which 
would have a new linker.  But, this isn't very helpful to you or 
to us httpd folks though.

I heard all of this second-hand via Aaron, so I may be missing
the key points, but I know the gist of the problem (AIX no gusto
DSOs).  I believe Aaron is lurking here, so he may be able to give 
more technical details and some pointers on what you may be able 
to do.

Therefore, I would consider focusing your efforts on getting mod_jk 
to work as it can be built as a self-contained DSO (it may require 
some hacking of the Makefiles though).  I think you will have a
much better chance of getting mod_jk to work than mod_webapp on 
AIX as a DSO.

> I have been informed by the management that if problem is not resolved by mid next week
Tomcat will be replaced with WebSphere 3.5 Standard Edition. 

Since you are running AIX, you may be best off being fully supported
by IBM - bite the bullet and use WebSphere 3.5.  You are already 
running their hardware, their OS, their HTTP server - their servlet 
engine isn't that much more to depend on.

Open-source projects can't fix IBM's closed-source linker.  -- justin

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