call_user_func

(PHP 4, PHP 5)

call_user_func — Call a user function given by the first parameter

Description

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

Call a user defined function given by the function parameter.

Parameters

function

The function to be called. Class methods may also be invoked statically using this function by passing array($classname, $methodname) to this parameter.

parameter

Zero or more parameters to be passed to the function.

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

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

$a = 0;
call_user_func('increment', $a);
echo $a; // 0

call_user_func_array('increment', array(&$a)); // You can use this instead
echo $a; // 1
?>

Return Values

Returns the function result, or FALSE on error.

Examples

Example #1 call_user_func() example

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

Example #2 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
// Hello world!
call_user_func(array(__NAMESPACE__ .'::Foo', 'test')); // As of PHP 5.3.0
// Hello world!

?>

Example #3 Using a class method

<?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

?>

Example #4 Using lambda function

<?php

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

?>

See Also

     

 

 
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