International PHP Conference Berlin 2023

Global space

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

Without any namespace definition, all class and function definitions are placed into the global space - as it was in PHP before namespaces were supported. Prefixing a name with \ will specify that the name is required from the global space even in the context of the namespace.

Example #1 Using global space specification

<?php
namespace A\B\C;

/* This function is A\B\C\fopen */
function fopen() { 
     
/* ... */
     
$f = \fopen(...); // call global fopen
     
return $f;

?>

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User Contributed Notes 5 notes

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64
routinet
11 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-
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15
nobody at example dot com
7 years 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
       
}
    }

}
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1
PhoneixSegovia at gmail dot com
3 months ago
Note that variables aren't part of the namespace so they are always global (or scoped to function, etc.) and can't be accessed the same way as other namespace stuff.

So no:

    namespace Foo;
    $var = "hello";
    echo \Foo\$var;
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-26
hileon at gmail dot com
7 years ago
This design of access globe name is bad, at least inconvenient.
In case that you have some legacy code, and try to copy and re-use it under some namespace. You have to add prefix "\" on any global function call.
up
-39
xmarcos at gmail dot com
10 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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