PHP全局变量和超全局变量

Question

$name = "张三 ";

function show_two() {

       //global $name;

       //$name = "李四";

$GLOBALS['name'] = "李四";

  }

global和$GLOBALS的区别?

什么时候使用global;

什么时候使用$GLOBALS?

Answer 1

关键字global声明的变量是在文档中拥有真正意义上的全局作用域的，而没有global声明的变量在函数内部是访问不了的，$GLOBALS包含了页面内的所有变量，包括所有的超全局预定义变量$_GET,$_POST,$_COOKIE,$_SESSION,$_SERVER,$_ENV等，它的作用域更广，在不同的页面都可访问到，函数内部也可以访问到，这两种都可以用，而要用到全局变量的情况不多，个人觉得如果用到，还是使用关键字global更好。

Answer 2

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