The role of the PHP keyword global in defining variables_PHP tutorial

We are using

If the PHP keyword global is used inside a function, it means that the variable used in this function is global, and the global variable is in the entire page It all works. For example

1. $conf = 1 ;
2. function conf_test() {
3. global $conf;
4. return ++$conf;
5. }
6. echo conf_test ()." >< br>"; echo conf_test()."
7. < br>"; Output:

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If there is no global $conf;, the output will be all 1. The function of the PHP keyword global is to declare that the $conf used in this function is not local, but globally available. In other words, the $conf defined inside the function is not a variable within the function, but the $conf defined outside the function (that is, $conf = 1;). In fact, it is easier to understand if the $GLOBALS array is used here. .

When we declare a variable $conf on the page, it is actually equivalent to defining an item $GLOBALS['conf'] in the $GLOBALS array. And this $GLOBALS is globally visible. So the above code is written in $GLOBALS format as

Output:

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute">conf</span><span> = </span><span class="attribute-value">1</span><span>;  </span></span></li>
<li><span>function conf_test() {  </span></li>
<li class="alt"><span>return ++$GLOBALS['conf'];  </span></li>
<li><span>}  </span></li>
<li class="alt">
<span>echo conf_test()."</span><span class="tag"><</span><span class="tag-name">br</span><span class="tag">></span><span>";  </span>
</li>
<li>
<span>echo conf_test()."</span><span class="tag"><</span><span class="tag-name">br</span><span class="tag">></span><span>"; </span>
</li>
</ol>

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PHP Keyword global

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www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446123.htmlTechArticleWe are using the PHP keyword global. If it is used inside a function, it means that the variable used in this function is global. Yes, global variables have an effect on the entire page. For example...