Call a callback with an array of parameters

Description

call_user_func_array ( callable $callback , array $param_arr ) : mixed

Calls the callback given by the first parameter with the parameters in param_arr.

Parameters

callback: The callable to be called.
param_arr: The parameters to be passed to the callback, as an indexed array.

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 #1 call_user_func_array() example


<?php
function foobar($arg, $arg2) {
    echo __FUNCTION__, " got $arg and $arg2\n";
}
class foo {
    function bar($arg, $arg2) {
        echo __METHOD__, " got $arg and $arg2\n";
    }
}


// Call the foobar() function with 2 arguments
call_user_func_array("foobar", array("one", "two"));

// Call the $foo->bar() method with 2 arguments
$foo = new foo;
call_user_func_array(array($foo, "bar"), array("three", "four"));
?>

The above example will output something similar to:

foobar got one and two
foo::bar got three and four

Example #2 call_user_func_array() using namespace name


<?php

namespace Foobar;

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

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

// As of PHP 5.3.0
call_user_func_array(array(__NAMESPACE__ .'\Foo', 'test'), array('Philip'));

?>

The above example will output something similar to:

Hello Hannes!
Hello Philip!

Example #3 Using lambda function


<?php

$func = function($arg1, $arg2) {
    return $arg1 * $arg2;
};

var_dump(call_user_func_array($func, array(2, 4))); /* As of PHP 5.3.0 */

?>

The above example will output:

int(8)

Example #4 Passing values by reference


<?php

function mega(&$a){
    $a = 55;
    echo "function mega \$a=$a\n";
}
$bar = 77;
call_user_func_array('mega',array(&$bar));
echo "global \$bar=$bar\n";

?>

The above example will output:

function mega $a=55
global $bar=55

Notes

Note:
Before PHP 5.4, referenced variables in param_arr are passed to the function by reference, regardless of whether the function expects the respective parameter to be passed by reference. This form of call-time pass by reference does not emit a deprecation notice, but it is nonetheless deprecated, and has been removed in PHP 5.4. Furthermore, this does not apply to internal functions, for which the function signature is honored. Passing by value when the function expects a parameter by reference results in a warning and having call_user_func() return FALSE (there is, however, an exception for passed values with reference count = 1, such as in literals, as these can be turned into references without ill effects — but also without writes to that value having any effect —; do not rely in this behavior, though, as the reference count is an implementation detail and the soundness of this behavior is questionable).

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.

call_user_func_array