View source for Manual:Wg variable

<languages />
{{#if:{{#translation:}}||{{DISPLAYTITLE:Manual:wg variable}}}}
<translate>
<!--T:1-->
'''wg''' refers to an important non-constant programming element used in the MediaWiki software, and is an abbreviation for "Wikipedia Global" (the naming pre-dates the spread of MediaWiki beyond [[w:Wikipedia|Wikipedia]]).
</translate>

<translate><!--T:2--> In general, any [[w:global variable|global variable]] (variable that has global [[w:Scope (programming)|scope]]) within the software has this prefix to make it easily identifiable when programming.</translate>
<translate><!--T:3--> However, a casual hacker will mainly come across such variables in the files <tvar name=1><code>includes/DefaultSettings.php</code></tvar> and <tvar name=2><code>{{ll|Manual:LocalSettings.php|LocalSettings.php}}</code></tvar>, which define variables to control the behavior of the software in various ways.</translate>

<translate>
<!--T:4-->
The <tvar name=1><code>{{ll|Manual:MainConfigSchema.php|MainConfigSchema.php}}</code></tvar> file stores the defaults for these values ''and should not be edited''; the <tvar name=2><code>LocalSettings</code></tvar> file is used to override these values for a specific site &mdash; if a particular variable is not mentioned in your <tvar name=2><code>LocalSettings</code></tvar> file, copy the entry from <tvar name=3><code>DefaultSettings</code></tvar> and amend as appropriate.</translate>

<translate><!--T:5--> Confusingly, MediaWiki code (mainly in <tvar name=1><code>OutputPage.php</code></tvar>) and extensions set a different (though overlapping) set of configuration variables in browser JavaScript, and many of these variables also have a <tvar name=2>'''wg'''</tvar> prefix (without PHP's <tvar name=3><code>$</code></tvar> sign).</translate>
<translate><!--T:6--> See <tvar name=mw-config>{{ll|Manual:Interface/JavaScript#mw.config}}</tvar> for a list.</translate>

<translate>
<!--T:7-->
Starting with the introduction of the <tvar name=Config>{{ll|Manual:Config.php|Config}}</tvar> class in MediaWiki 1.23, the "wg" prefix for PHP global variables is being phased out as configuration settings are moving away from global scope.

== See also == <!--T:8-->

<!--T:9-->
* [[<tvar name=conventions>Manual:Coding conventions/PHP#Variables</tvar>|Manual:Coding conventions/PHP#Variables]] for other variable prefixes used in MediaWiki.</translate>
<translate>
<!--T:10-->
* <tvar name=1>{{ll|Manual:Configuration settings}}</tvar> contains a list of all customization settings defined as global variables in MediaWiki. These can be configured in <tvar name=LocalSettings>{{ll|Manual:LocalSettings.php|LocalSettings.php}}</tvar>.
</translate>
* {{ll|Manual:Global object variables}} - <translate><!--T:11--> lists some of the main global variables that aren't customization settings.</translate>

[[Category:MediaWiki technical documentation{{#translation:}}]]