====== Xdebug ======
Xdebug is a php debugger.  It allows a developer to debug php applications in a similar manner to that of other languages.  Clients can connect to xdebug remotely.  NetBeans is an example of a remote client.

  * first install [[apache2]], and [[php]]
    * (:!: php will need built WITH cli for command line testing, so don't use %%--disable-cli%% flag)
  * download source from http://www.xdebug.org
  * :-) make sure to install the xt.vim file and configure your filetypes as per the xdebug documentation, to gain syntax highlighting and folding in Vim
  * view README to see if process has changed
  * in the root of the extracted files...<code>
phpize

./configure --enable-xdebug

make

sudo cp modules/xdebug.so /usr/local/apache2/modules/

sudo chown www:www /usr/local/apache2/modules/xdebug.so
</code>
  * edit php.ini (if php was built as shown on this wiki, edit or create php.ini in /usr/local/lib)<code>
; set up xdebug
zend_extension="/usr/local/apache2/modules/xdebug.so"
xdebug.remote_enable=1
xdebug.trace_enable_triger=1
xdebug.trace_output_dir="/tmp"
xdebug.trace_output_name="trace.%R"
xdebug.profiler_enable_triger=1
xdebug.profiler_output_dir="/tmp"
xdebug.profiler_output_name="cachegrind.out.%R"
;xdebug.remote_handler=dbgp
;xdebug.remote_host=localhost
;xdebug.remote_port=9000
</code>
  * restart apache: ''sudo /usr/local/apache2/bin/apachectl -k graceful''
  * view a phpinfo() page to verify that the xdebug module is loaded
  * for typical debugging, you probably want to get helper extensions in Chrome or Firefox which easily set cookies appropriately for debugging, profiling, and tracing; then connect with something like Vdebug for Vim, or with Netbeans
  * for a simple function call dump in php, use one of these lines:<code php>
// make sure the web server can write to this directory, or the
// file won't show up!!
xdebug_start_trace(getcwd() . "/trace", XDEBUG_TRACE_APPEND);
xdebug_start_trace(getcwd() . "/trace");
</code>
  * other settings for function dumps can be tweaked to show passed parameters, return values, etc...<code>
ini_set("xdebug.collect_params", 3);
xdebug.collect_includes = On
ini_set("xdebug.collect_return", 1);
xdebug.show_mem_delta = On
</code>

===== Debugging =====
  * to debug from command line, start a debugging listener client such as Netbeans or XDebugClient and run like this:<code php>
php -dxdebug.remote_autostart=On myprogram.php
</code>
  * Be sure to download Xdebug Helper extension (Chrome), or The easiest Xdebug (Firefox).  You then start a listening client and refresh any php page on a server with xdebug installed.
  * for more information, see NetBeans or other client documentation on how to debug

===== xdebug gotchas =====
xdebug overloads several php functions, so they don't work exactly as they did before.
  * var_dump is limited in certain ways by default; one of these items is the maximum children that can be displayed before you get the message "more elements..."; to fix this, set this parameter:<code>
ini_set("xdebug.var_display_max_children", -1);
</code>