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call_user_func_array

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

call_user_func_array — Call a callback with an array of parameters

Beschreibung

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

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

Parameter-Liste

callback

The callable to be called.

args

The parameters to be passed to the callback, as an array.

If the keys of args are all numeric, the keys are ignored and each element will be passed to callback as a positional argument, in order.

If any keys of args are strings, those elements will be passed to callback as named arguments, with the name given by the key.

It is a fatal error to have a numeric key in args appear after a string key, or to have a string key that does not match the name of any parameter of callback.

Rückgabewerte

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

Changelog

Version	Beschreibung
8.0.0	`args` keys will now be interpreted as parameter names, instead of being silently ignored.

Beispiele

Beispiel #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"));
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

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

Beispiel #2 call_user_func_array() using namespace name

<?php

namespace Foobar;

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

call_user_func_array(__NAMESPACE__ .'\Foo::test', array('Hannes'));

call_user_func_array(array(__NAMESPACE__ .'\Foo', 'test'), array('Philip'));

?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

Hello Hannes!
Hello Philip!

Beispiel #3 Using lambda function

<?php

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

var_dump(call_user_func_array($func, array(2, 4)));

?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

int(8)

Beispiel #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";

?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

function mega $a=55
global $bar=55

Beispiel #5 call_user_func_array() using named arguments

<?php
function foobar($first, $second) {
    echo __FUNCTION__, " got $first and $second\n";
}

// Call the foobar() function with named arguments in non-positional order
call_user_func_array("foobar", array("second" => "two", "first" => "one"));

// Call the foobar() function with one named argument
call_user_func_array("foobar", array("foo", "second" => "bar"));

// Fatal error: Cannot use positional argument after named argument
call_user_func_array("foobar", array("first" => "one", "bar"));

?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

foobar got one and two
foobar got foo and bar

Fatal error: Uncaught Error: Cannot use positional argument after named argument

Anmerkungen

Hinweis:
Callbacks, die für Funktionen wie call_user_func() und call_user_func_array() registriert sind, werden nicht mehr ausgeführt, wenn in einem vorherigen Callback eine Exception geworfen und nicht gefangen wurde.

Siehe auch

call_user_func() - Ruft die Callback-Funktion auf, die als erster Parameter übergeben wurde
ReflectionFunction::invokeArgs() - Invokes function args
ReflectionMethod::invokeArgs() - Invoke args

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User Contributed Notes 4 notes

down

admin at torntech dot com ¶

9 years ago


As of PHP 5.6 you can utilize argument unpacking as an alternative to call_user_func_array, and is often 3 to 4 times faster.

<?php
function foo ($a, $b) {
     return $a + $b;
}

$func = 'foo';
$values = array(1, 2);
call_user_func_array($func, $values); 
//returns 3

$func(...$values);
//returns 3
?>

Benchmarks from https://gist.github.com/nikic/6390366
cufa   with 0 args took 0.43453288078308
switch with 0 args took 0.24134302139282
unpack with 0 args took 0.12418699264526
cufa   with 5 args took 0.73408579826355
switch with 5 args took 0.49595499038696
unpack with 5 args took 0.18640494346619
cufa   with 100 args took 5.0327250957489
switch with 100 args took 5.291127204895
unpack with 100 args took 1.2362589836121

down

sebastian dot rapetti at tim dot it ¶

3 years ago


Using PHP 8, call_user_func_array call callback function using named arguments if an array with keys is passed to $args parameter, if the array used has only values, arguments are passed positionally.

<?php

function test(string $param1, string $param2): void
{
    echo $param1.' '.$param2;
}

$args = ['hello', 'world'];
//hello world
call_user_func_array('test', $args);

$args = ['param2' => 'world', 'param1' => 'hello'];
//hello world
call_user_func_array('test', $args);

$args = ['unknown_param' => 'hello', 'param2' => 'world'];
//Fatal error: Uncaught Error: Unknown named parameter $unknown_param
call_user_func_array('test', $args);
?>

down

alangiderick at gmail dot com ¶

1 year ago


It's quite interesting reading the notes in this page especially the one that mentions the difference between argument unpacking being significantly faster than calling `call_user_func_array()` directly by admin at torntech dot com.

This is true for PHP 5 but as from PHP 7.0+, there is no significant difference in the run-time between these two mechanisms of operation. The time taken is almost, if not the same for both operations, so this is already something that tells me that the PHP run-time environment has changed quite a lot (for the PHP 7 rewrite).

I used the example from admin at torntech dot com to check this hypothesis.

down

-2

james at gogo dot co dot nz ¶

20 years ago


Be aware the call_user_func_array always returns by value, as demonstrated here...

<?php    
    function &foo(&$a)
    {
      return $a;
    }
    
    $b = 2;
    $c =& call_user_func_array('foo', array(&$b));
    $c++;
    echo $b . ' ' . $c;    
?>

outputs "2 3", rather than the expected "3 3".

Here is a function you can use in place of call_user_func_array which returns a reference to the result of the function call. 

<?php
    function &ref_call_user_func_array($callable, $args)
    {
        if(is_scalar($callable))
        {
            // $callable is the name of a function
            $call = $callable;
        }
        else
        {
            if(is_object($callable[0]))
            {
                // $callable is an object and a method name
                $call = "\$callable[0]->{$callable[1]}";
            }
            else
            {
                // $callable is a class name and a static method
                $call = "{$callable[0]}::{$callable[1]}";
            }
        }
        
        // Note because the keys in $args might be strings
        // we do this in a slightly round about way.
        $argumentString = array();
        $argumentKeys = array_keys($args);
        foreach($argumentKeys as $argK)
        {
            $argumentString[] = "\$args[$argumentKeys[$argK]]";
        }
        $argumentString = implode($argumentString, ', ');
        // Note also that eval doesn't return references, so we 
        // work around it in this way...    
        eval("\$result =& {$call}({$argumentString});");
        return $result;
    }
?>

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