get_parent_class

    (PHP 4, PHP 5, PHP 7, PHP 8)

    get_parent_class — Retrieves the parent class name for object or class

    Description

    get_parent_class(object|string $object_or_class = ?): string|false

    Retrieves the parent class name for object or class.

    Parameters

    object_or_class

    The tested object or class name.

    Return Values

    Returns the name of the parent class of the class of which object_or_class is an instance or the name.

    If the object does not have a parent or the given class does not exist, false will be returned.

    Changelog

    Version Description
    8.3.0 Calling get_parent_class() without an argument now emits an E_DEPRECATED warning; previously, calling this function inside a class returned the name of that class.
    8.0.0 The object_or_class parameter now only accepts objects or valid class names.

    Examples

    Example #1 Using get_parent_class()

    <?php

    class Dad {
    function     __construct()
    {
    // implements some logic
    }
    }

    class     Child extends Dad {
    function     __construct()
    {
    echo     "I'm " , get_parent_class($this) , "'s son\n";
    }
    }

    class     Child2 extends Dad {
    function     __construct()
    {
    echo     "I'm " , get_parent_class('child2') , "'s son too\n";
    }
    }

    $foo = new child();
    $bar = new child2();

    ?>

    The above example will output:

    I'm Dad's son
I'm Dad's son too

    See Also

    • get_class() - Returns the name of the class of an object
    • is_subclass_of() - Checks if the object has this class as one of its parents or implements it
    • class_parents() - Return the parent classes of the given class

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    User Contributed Notes 7 notes

    up
    7
    yukal dot alexander at gmail dot com
    5 years ago
    An output of the entire inheritance chain using closures, recursion, and OOP

    class ParentClass {
    public static function getChain() {
    $chain = null;
    return $function = function($className='') use (& $chain, & $function) {
    if (empty($className))
    $className = static::class;

    if (empty($chain))
    $chain = $className;

    $parent = get_parent_class($className);

    if ($parent !== false) {
    $chain .= " > {$parent}";
    return $function($parent);
    }

    return $chain;
    };
    }
    }

    class Child extends ParentClass {}
    class SubChild extends Child {}
    class Sub2 extends SubChild {}
    class Sub3 extends Sub2 {}
    class Sub4 extends Sub3 {}
    class Sub5 extends Sub4 {}
    class Sub6 extends Sub5 {}
    class Sub7 extends Sub6 {}

    printf("%s\n", Sub7::getChain()());

    $getChain = Sub7::getChain();
    printf("%s\n", $getChain('Sub3'));

    Output is:
    Sub7 > Sub6 > Sub5 > Sub4 > Sub3 > Sub2 > SubChild > Child > ParentClass
    Sub3 > Sub2 > SubChild > Child > ParentClass
    up
    1
    jake at qzdesign dot co dot uk
    4 years ago
    Note that from PHP 5.5 you can also use `parent::class` from within a method, e.g.

    <?php
    function child()
    {
    echo     "I'm ", parent::class, "'s son\n";
    }
    ?>

    Looks a bit tidier and technically probably more optimal, as it avoids a function call lookup.
    up
    1
    falundir at gmail dot com
    12 years ago
    You can use this function to find common parent of multiple objects or classes.

    <?php
    /**
    * Returns name of the first (in class hierarchy) common parent class of all provided objects or classes.
    * Returns FALSE when common class is not found.
    *
    * @param mixed $objects Array that can contain objects or class names.
    * @return mixed
    */
    function get_first_common_parent($objects) {
    $common_ancestors = null;
    foreach(    $objects as $object) {
    if (    is_object($object)) {
    $class_name = get_class($object);
    } else {
    $class_name = $object;
    }

    $parent_class_names = array();
    $parent_class_name = $class_name;
    do {
    $parent_class_names[] = $parent_class_name;
    } while(    $parent_class_name = get_parent_class($parent_class_name));

    if (    $common_ancestors === null) {
    $common_ancestors = $parent_class_names;
    } else {
    $common_ancestors = array_intersect($common_ancestors, $parent_class_names);
    }
    }

    return     reset($common_ancestors);
    }
    ?>

    Example:

    <?php
    class A {
    }

    class     B extends A {
    }

    class     D extends B {
    }

    class     E extends B {
    }

    class     C extends A {
    }

    class     F extends C {
    }

    class     G extends F {
    }

    class     H {
    }

    //returns "A"
    get_first_common_parent(array('G', 'E'));

    //returns "F"
    get_first_common_parent(array(new G(), 'F'));

    //returns false (no common parent)
    get_first_common_parent(array('C', 'H'));

    //returns false (non-existent class provided)
    get_first_common_parent(array(new B(), 'X'));
    ?>
    up
    1
    levu
    13 years ago
    I wrote a simple function doing the reverse thing: get the children:

    <?php
    function get_child($instance, $classname) {
    $class = $classname;
    $t = get_class($instance);
    while ((    $p = get_parent_class($t)) !== false) {
    if (    $p == $class) {
    return     $t;
    }
    $t = $p;
    }
    return     false;
    }

    abstract class     A {
    function     someFunction() {
    return     get_child($this, __CLASS__);
    }
    }

    class     B extends A {

    }

    class     C extends B {

    }

    $c = new C();
    echo     $c->someFunction(); //displays B

    ?>
    up
    0
    ssb45 at cornell dot edu
    16 years ago
    "'If called without parameter outside object' What on earth does that mean?"

    There are two places this could be called:
    1. From within a member function of an object. In this case, it may be called with no parameters and will return the parent class of the object owning the member function. (If the parameter is included, then it will return the parent class of the specified class as normal.)

    2. From outside an object (i.e., global or function scope). In this case, PHP doesn't know what class you're talking about if you don't include a parameter, so it returns FALSE. (But, of course, it works if you specify the class with the parameter.)
    up
    0
    matt-php at DONT-SPAM-ME dot bitdifferent dot com
    19 years ago
    PHP (4 at least, dunno about 5) stores classnames in lower case, so:

    <?PHP

    class Foo
    {
    }

    class     Bar extends Foo
    {
    }

    echo     get_parent_class('Bar');

    echo     "\n";

    echo     get_parent_class('bar');

    ?>

    will output:

    foo
    foo
    up
    -1
    radu dot rendec at ines dot ro
    20 years ago
    If the argument obj is a string and the class is not defined, then the function returns FALSE.

    If the argument obj is an object created from a class with no ancestors (or a string representing a class with no ancestors), then the function returns FALSE.
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