php教程

get_declared_classes

(PHP 4, PHP 5, PHP 7)

get_declared_classes — 返回由已定义类的名字所组成的数组

说明

get_declared_classes ( void ) : array

返回由当前脚本中已定义类的名字组成的数组。

返回值

返回由当前脚本中已定义类的名字组成的数组。

Note:

需要注意的是额外类的出现依赖于你已编译到 PHP 中的库。这意味着你不能使用这些类名定义自己的类。在附录的 预定义类 部分有预定义类的列表。

范例

Example #1 get_declared_classes() 例子

<?php
print_r(get_declared_classes());
?>

以上例程的输出类似于：

Array
(
    [0] => stdClass
    [1] => __PHP_Incomplete_Class
    [2] => Directory
)

参见

User Contributed Notes

brain at code dot com 14-Feb-2014 08:53
get-declared-classes makes no sense at all, if u maybe, later for production, merge class files in one package file.

lets say: package.php
print_r(get_declared_classes());
class declaredHere { }
print_r(get_declared_classes());

so in this case, the declaredHerr class is defined at the first call of print_r();
because PHP-complier runs a hole file and declare Stuff before running the code.

But (Lovely PHP):
print_r(get_declared_classes());
if(true){
class declaredHere { }
}
print_r(get_declared_classes());
Will print the declaredHere class only in the second print_r.

Its not a Bug it a...
yarco dot wang at gmail dot com 24-Nov-2013 07:32
those above comments are too old.
now, whatever the order is, the output will be the same:

<?php
class Test1
{}

print_r(get_declared_classes());

class Test2
{}

print_r(get_declared_classes());

?>

will output the same result.
dcahh at gmx de 29-Feb-2008 09:23
This function considers only classes and subclasses. Not subsubclasses.

In fact I have code that provides an abstract class and then classes using this abstract class. Further I have subclasses to my concrete classes - which is why my subclasses are not listed within the returned array.
dexen + goofy _ pl 25-Sep-2007 11:32
Summary:
 * in PHP 5.1 class names have case preserved
 * contrary, in PHP 4.4 class names are downcased, withe exception of a few build-in ones

The get_declared_classes() funcition returns the list of names with case preserved, as of PHP 5.1 series (prolly 5.0 too, but i have no way to test it right now). Since PHP generally is caseless in regard to names of classes, this may come at a surprise. Also, this could potentially break older code asssuming downcased list.

Take extra care when  checking for existence of a class. Following example is, potentially, error prone: <?php in_array( $className, $classget_declared_classes() ) ?>

A sure-fire (while slower) way would be to iterate over the array and normalize case to, say, lower:

<?php
$exists = FALSE;
$className = strtolower( $className );
foreach ( get_declared_classes() as $c ) {
    if ( $className === strtolower( $c ) ) {
        $exists = TRUE;
        break;
    }
}?>

Optimization of the above snippet is left as a simple excercise to the reader ;)
-- dexen deVries
matt at mattsoft dot net 21-Dec-2005 02:58
classes can't be unloaded. probably not very practical to implement that in a future version. I wouldn't go out of my way to do it if I were zend. you're better off finding a workaround. it's better programming technique to find a way around having to do that anyway.

http://www.zend.com/zend/week/week223.php#Heading10
22-Mar-2005 09:16
Regarding note of 3-21:

<?php

class myclass {}

$class = 'myclass';
$instance = new $class();

?>

This function could also be used to determine the names of classes defined in a particular file by calling it before and after include. It's hardly a pointless function.
matt-php at DONT-SPAM-ME dot bitdifferent dot com 01-Nov-2004 07:41
The array returned by this function will be in the order the classes were defined / included / required and this order does not appear to change.

For example:

<?PHP

//define classone
class classone { }

//define classtwo
class classtwo { }

//This will show X classes (built-ins, extensions etc) with
//classone and classtwo as the last two elements

print_r(get_declared_classes());

//define classthree
class classthree { }

//...and four
class classfour { }

//Shows the same result as before with class three and four appended
print_r(get_declared_classes());

?>

Output:

Array
(
   [0] => stdClass
   [1] .... other defined classes....
   [10] => classone
   [11] => classtwo
 )

and...

Array
(
   [0] => stdClass
   [1] .... other defined classes....
   [10] => classone
   [11] => classtwo
   [12] => classthree
   [13] => classfour
)
Jazeps Basko 07-Feb-2004 11:52
In PHP5, you don't get declared interfaces by calling this function!!!
To get interfaces you should use get_declared_interfaces(). However, to check if an interface is already defined, you should use class_exists()! This is strange, but PHP team does not think so.
smokey 20-Mar-2003 03:06
you cannot remove them. they are "defined", which happens when the class is being loaded from the parser. you just deleted an instance of a class.

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