Scholar Repository
Home>Manual>Call a user function given by the first parameter

Call a user function given by the first parameter


call_user_func

(PHP 4, PHP 5)

call_user_funcCall 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, $methodname) to this parameter. Additionally class methods of an object instance may be called by passing array($objectinstance, $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.

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 function result, or FALSE on error.

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


Home>Manual>Call a user function given by the first parameter