I am running Apache2 on a Mac OS X (10.5). I just compiled PHP 5.2.8 and finally got pdo-mysql working (or so I think).

This terminal command:

php --version

is showing 5.2.8 and I have the right modules installed.

But, when I do a phpinfo(), Apache dumps out PHP 5.2.6 (my earlier version, without pdo_mysql).

How do I tell Apache which PHP to load? The httpd.conf has the line:

LoadModule php5_module        libexec/apache2/libphp5.so

But, I don't know what or where that is.

Is that what I have to change?

  • When you compiled php did you use make install? If you did find the path that it installed your module to and change your apache config to point to it. Mac has it's own version of apache and php5 already installed which is why you are seeing a different version.
    – Ruggs
    Dec 23, 2008 at 3:25
  • 1
    See OSX Apache using wrong version of PHP
    – Mick
    Mar 3, 2014 at 13:12
  • Homebrew users, see @Mick comment Dec 8, 2015 at 17:44
  • 1
    Did you solve your problem? ALL the answers are just mad thing Mar 3, 2017 at 14:29
  • None of these responses answer the question. This is bizarre...
    – quant
    Dec 28, 2018 at 9:02

5 Answers 5


I think all these answers aren't really answering the question. The root level can be determined by running the command httpd -V. This will show you what options the Apache daemon was built with at compile time. This is what controls where httpd determines where to look for it's config. files and .so modules by default.

For example:

% httpd -V
Server version: Apache/2.2.17 (Unix)
Server built:   Dec 17 2010 11:58:24
Server's Module Magic Number: 20051115:25
Server loaded:  APR 1.3.12, APR-Util 1.3.9
Compiled using: APR 1.3.12, APR-Util 1.3.9
Architecture:   32-bit
Server MPM:     Prefork
  threaded:     no
    forked:     yes (variable process count)
Server compiled with....
 -D APACHE_MPM_DIR="server/mpm/prefork"
 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
 -D HTTPD_ROOT="/etc/httpd"
 -D SUEXEC_BIN="/usr/sbin/suexec"
 -D DEFAULT_PIDLOG="logs/httpd.pid"
 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
 -D DEFAULT_LOCKFILE="logs/accept.lock"
 -D DEFAULT_ERRORLOG="logs/error_log"
 -D AP_TYPES_CONFIG_FILE="conf/mime.types"
 -D SERVER_CONFIG_FILE="conf/httpd.conf"

The key line in that output is the HTTPD_ROOT. That defines where Apache's ROOT directory is to start, /etc/httpd in my case, when looking for config. files and modules.

NOTE: This ROOT is not the same thing as DocumentRoot. This ROOT is specific to how the httpd daemon was compiled, the DocumentRoot is for specifying where the httpd daemon should start looking for actual web content (.html files and such).

For my httpd.conf file I have the following Load lines:

LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule auth_digest_module modules/mod_auth_digest.so
LoadModule authn_file_module modules/mod_authn_file.so

Given this the full path to your modules would be, for example:


This is from a CentOS 5.x system but the technique is still apt.

BTW, it can get a little confusing because in CentOS' case the files are organized physically here:

% ls /usr/lib/httpd/modules/
libphp5.so            mod_authnz_ldap.so      mod_dav_fs.so      mod_headers.so       mod_perl.so            mod_speling.so

...and then accessible to the Apache daemon, httpd, through this path:

% ls -l /etc/httpd/
total 12
drwxr-xr-x 2 root root 4096 Apr 26  2011 conf
drwxr-xr-x 3 root root 4096 Apr 26  2011 conf.d
-rw-r--r-- 1 root root   18 Feb 24  2009 htpasswd
lrwxrwxrwx 1 root root   19 Apr 26  2011 logs -> ../../var/log/httpd
lrwxrwxrwx 1 root root   27 Apr 26  2011 modules -> ../../usr/lib/httpd/modules
lrwxrwxrwx 1 root root   13 Apr 26  2011 run -> ../../var/run

The modules link connects /etc/httpd --> /usr/lib/httpd/modules.

  • slm as i stated in the previous post, the ServerRoot is defined in the ServerRoot directive and has nothing whatsoever to do with HTTPD_ROOT which is displayed via "httpd -V." Please consult Apache's web pages referenced in my previous post, or if you'd like change the ServerRoot directive in your httpd.conf file and see for yourself. Jan 18, 2013 at 8:45
  • ServerRoot is a way to overrride HTTPD_ROOT. HTTPD_ROOT is set at compile time via the --prefix configure switch. Your post was distinguishing the different b/w ServerRoot and DocumentRoot. httpd.apache.org/docs/current/mod/core.html#serverroot. Good to see you registered a name with your SF account!
    – slm
    Jan 18, 2013 at 13:07
  • Does this really answer the question: "How do I tell Apache which PHP to use?" ? Mar 3, 2017 at 14:20
  • Trix the OP accepted it so yes.
    – slm
    Mar 3, 2017 at 14:35
  • @slm This does not answer the question.
    – quant
    Dec 28, 2018 at 9:01

You can find files on your system with the locate command:

# locate libphp5.so

It will print the full paths of all files with that name. I have one at /usr/libexec/apache2/libphp5.so.

  • 2
    So what? is this an answer to the question? Or a way to find a file? Mar 3, 2017 at 14:27
  • 1
    @Trix, the asker said, "I don't know what or where that is." I've shown how to find where that is. I assumed that once the asker saw all the other locations of the named file in question, it would be apparent how to change the setting to use a different one. Mar 3, 2017 at 14:50

The parent directory of modules loaded in httpd.conf (such as: libexec/apache2/libphp5.so) is defined by the ServerRoot directive which by default is typically set to /usr. I wouldn't recommend changing this but it may be useful for someone to know just where exactly that path is defined.

Apache's website says the following about ServerRoot:

Relative paths in other configuration directives (such as Include or LoadModule, for example) are taken as relative to this directory.

additionally the default httpd.conf file comments read:

ServerRoot: The top of the directory tree under which the server's configuration, error, and log files are kept.

  • 2
    The OP is not after a definition to ServerRoot. Instead (s)he has asked the question "How do I tell Apache which PHP to use?". If you really want to answer it, so answer it Mar 3, 2017 at 14:22

Apache should be looking for modules in "/usr/libexec/httpd/". In there you'll find either a file or symlink called "libphp5.so". If it's a symlink, you'll need to relink to the new 5.2.8 libphp5.so, otherwise just copy the 5.2.8 libphp5.so to "/usr/libexec/httpd/" and restart apache with "sudo apachectl restart".


I had a Apache and PHP installed on one of the server. This was installed by the previous sys admin. Both the Apache and PHP was complied from the source. In addition to this there was a default PHP installed. So to know which PHP is used by the Apache. I run the below command

   <Install Dir of PHP>/bin/php -i | grep apxs

This gave me the path to apache apxs


This gave me info on which Apache is being used by this php. The default php gave error when i typed

#php -i | grep apxs 

 Failed loading opcache.so:  opcache.so: cannot open shared object file: No    such file or directory PHP Warning:  PHP Startup: Unable to load dynamic library     '<PHP_HOME>/lib/php/extensions/debug-non-zts-20121212/memcached.so' - <PHP_HOME>/lib/php/extensions/debug-non-zts-20121212/memcached.so: undefined symbol: OnUpdateLongGEZero in Unknown on line 0

So in this way i was able to figure out the php used by Apache.

  • 1
    Please don't post the same answer twice. Instead, link to the first answer.
    – Sven
    Mar 27, 2015 at 22:40

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