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call_user_func

(PHP 4, PHP 5)

call_user_funcCall the callback given by the first parameter

Description

mixed call_user_func ( callable $callback [, mixed $parameter [, mixed $... ]] )

Calls the callback given by the first parameter and passes the remaining parameters as arguments.

Parameters

callback

The callable to be called.

parameter

Zero or more parameters to be passed to the callback.

Note:

Note that the parameters for call_user_func() are not passed by reference.

Example #1 call_user_func() example and references

<?php
error_reporting
(E_ALL);
function 
increment(&$var)
{
    
$var++;
}

$a 0;
call_user_func('increment'$a);
echo 
$a."\n";

call_user_func_array('increment', array(&$a)); // You can use this instead before PHP 5.3
echo $a."\n";
?>

The above example will output:

0
1

Return Values

Returns the return value of the callback, or FALSE on error.

Changelog

Version Description
5.3.0 The interpretation of object oriented keywords like parent and self has changed. Previously, calling them using the double colon syntax would emit an E_STRICT warning because they were interpreted as static.

Examples

Example #2 call_user_func() example

<?php
function barber($type)
{
    echo 
"You wanted a $type haircut, no problem\n";
}
call_user_func('barber'"mushroom");
call_user_func('barber'"shave");
?>

The above example will output:

You wanted a mushroom haircut, no problem
You wanted a shave haircut, no problem

Example #3 call_user_func() using namespace name

<?php

namespace Foobar;

class 
Foo {
    static public function 
test() {
        print 
"Hello world!\n";
    }
}

call_user_func(__NAMESPACE__ .'\Foo::test'); // As of PHP 5.3.0
call_user_func(array(__NAMESPACE__ .'\Foo''test')); // As of PHP 5.3.0

?>

The above example will output:

Hello world!
Hello world!

Example #4 Using a class method with call_user_func()

<?php

class myclass {
    static function 
say_hello()
    {
        echo 
"Hello!\n";
    }
}

$classname "myclass";

call_user_func(array($classname'say_hello'));
call_user_func($classname .'::say_hello'); // As of 5.2.3

$myobject = new myclass();

call_user_func(array($myobject'say_hello'));

?>

The above example will output:

Hello!
Hello!
Hello!

Example #5 Using lambda function with call_user_func()

<?php
call_user_func
(function($arg) { print "[$arg]\n"; }, 'test'); /* As of PHP 5.3.0 */
?>

The above example will output:

[test]

Notes

Note:

Callbacks registered with functions such as call_user_func() and call_user_func_array() will not be called if there is an uncaught exception thrown in a previous callback.

See Also

PHP Manual