title: How to enable pthreads in PHP 5.6.13 at CentOS 6.7?
body: <p>I have PHP 5.6.13 installed at CentOS 6.7 through IUS repositories. This is the output of <code>php -v</code> command:</p>
  
  <pre><code># php -v
  PHP 5.6.13 (cli) (built: Sep  3 2015 11:54:03)
  Copyright (c) 1997-2015 The PHP Group
  Zend Engine v2.6.0, Copyright (c) 1998-2015 Zend Technologies
      with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies
      with Xdebug v2.3.3, Copyright (c) 2002-2015, by Derick Rethans
  </code></pre>
  
  <p>For install and enable <code>pthreads</code> I have follow this steps:</p>
  
  <ol>
  <li><p>Search the proper packages:</p>
  
  <pre><code># yum search pthreads
  ================================= N/S Matched: pthreads ===============================
  mingw32-winpthreads-static.noarch : Static version of the MinGW Windows pthreads library
  mingw64-winpthreads-static.noarch : Static version of the MinGW Windows pthreads library
  php55u-pecl-pthreads-debuginfo.x86_64 : Debug information for package php55u-pecl-pthreads
  php56u-pecl-pthreads-debuginfo.x86_64 : Debug information for package php56u-pecl-pthreads
  mingw32-winpthreads.noarch : MinGW pthread library for the win32 target
  mingw64-winpthreads.noarch : MinGW pthread library for the win64 target
  openblas-threads.i686 : An optimized BLAS library based on GotoBLAS2, pthreads version
  openblas-threads.x86_64 : An optimized BLAS library based on GotoBLAS2, pthreads version
  php55u-pecl-pthreads.x86_64 : Threading API
  php56u-pecl-pthreads.x86_64 : Threading API
  </code></pre></li>
  <li><p>Install the package:</p>
  
  <pre><code>#yum install php56u-pecl-pthreads.x86_64
  
  Resolving Dependencies
  --&gt; Running transaction check
  ---&gt; Package php56u-pecl-pthreads.x86_64 0:2.0.10-2.ius.el6 will be installed
  --&gt; Finished Dependency Resolution
  
  Dependencies Resolved
  =======================================================================================================================================================================================================================================
   Package                                                         Arch                                              Version                                                        Repository                                      Size
  =======================================================================================================================================================================================================================================
  Installing:
   php56u-pecl-pthreads                                            x86_64                                            2.0.10-2.ius.el6                                               ius                                             71 k
  
  Transaction Summary
  =======================================================================================================================================================================================================================================
  Install       1 Package(s)
  </code></pre></li>
  <li><p>Locate where the <code>.so</code> did go:</p>
  
  <pre><code>#locate pthreads.so
  /usr/lib64/php-zts/modules/pthreads.so
  </code></pre></li>
  <li><p>Enable at <code>/etc/php.ini</code> by trying each of the following lines:</p>
  
  <pre><code>extension=pthreads.so
  extension=/usr/lib64/php-zts/modules/pthreads.so
  zend_extension=pthreads.so
  zend_extension=/usr/lib64/php-zts/modules/pthreads.so
  </code></pre></li>
  <li><p>Restarted Apache and find for the module</p>
  
  <pre><code># php -m | grep pthreads
  Failed loading /usr/lib64/php-zts/modules/pthreads.so:  /usr/lib64/php-zts/modules/pthreads.so: undefined symbol: core_globals_id
  </code></pre></li>
  </ol>
  
  <p>And all the time it fails with the message above. What I am doing wrong?</p>
  
  <p><strong>Note:</strong> I have notice by running <code>phpinfo()</code> that <code>Thread Safety</code> is disabled, do I need this enabled in order to properly load the library?</p>