php[world] 2015 Schedule Announced

全局空间

如果没有定义任何命名空间,所有的类与函数的定义都是在全局空间,与 PHP 引入命名空间概念前一样。在名称前加上前缀 \ 表示该名称是全局空间中的名称,即使该名称位于其它的命名空间中时也是如此。

Example #1 使用全局空间说明

<?php
namespace A\B\C;

/* 这个函数是 A\B\C\fopen */
function fopen() { 
     
/* ... */
     
$f = \fopen(...); // 调用全局的fopen函数
     
return $f;

?>

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User Contributed Notes 3 notes

up
11
routinet
3 years ago
Included files will default to the global namespace.
<?php
//test.php
namespace test {
  include
'test1.inc';
  echo
'-',__NAMESPACE__,'-<br />';
}
?>

<?php
//test1.inc
 
echo '-',__NAMESPACE__,'-<br />';
?>

Results of test.php:

--
-test-
up
1
nobody at example dot com
1 month ago
In namespaced context the Exception class needs to be prefixed with global prefix operator.

<?php

namespace hey\ho\lets\go;

class
MyClass
{
    public function
failToCatch()
    {
        try {
           
$thing = somethingThrowingAnException();
        } catch (
Exception $ex) {
             
// Not catched
       
}
    }

    public function
succeedToCatch()
    {
        try {
           
$thing = somethingThrowingAnException();
        } catch (\
Exception $ex) {
             
// This is now catched
       
}
    }

}
up
-11
xmarcos at gmail dot com
3 years ago
That's the expected behavior, you have to declare the namespace at the top of the file to "extend" it.

If you include a global namespaced file, it will operate on the global namespace.
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