1/31/2006
Undefined Symbol Error After Installing Zend Optimizer
I recently had a hard time installing Zend Optimizer on a CentOS 4 server. When starting Apache after the install, this was logged to the Apache error_log:
Failed loading /usr/local/lib/ZendExtensionManager.so: /usr/local/lib/ZendExtensionManager.so: undefined symbol: zend_extensions
Apache started up and ran, but no Zend Optimizer listed in the phpinfo page. Further weirdness had CLI PHP (command line PHP) showing the optimizer installed:
[root@www ~]# php -i | grep ptimizer
25: with Zend Optimizer v2.6.2, Copyright (c) 1998-2006, by Zend Technologies
355:Zend Optimizer
25: with Zend Optimizer v2.6.2, Copyright (c) 1998-2006, by Zend Technologies
355:Zend Optimizer
A little Googling found this post over at the Zend forums.
Recompiling PHP without versioning corrected the problem and allowed the Zend Optimizer to load up in Apache/PHP.
Popularity: 21%



February 17th, 2006 at 12:24 pm
Thanks for the info. I don’t think this applies to i386 systems, only x86_64 systems. We’ve been using versioning forever and only found out about this since we switched over to using Opterons.
This also fixes issues with eAccellerator, too.
February 17th, 2006 at 12:29 pm
This was on an i686 Athlon, CentOS release 4.2 (Final) box.