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

    Description

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

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

    Parameters

    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.

    Return Values

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

    Changelog

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

    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";
    }
    }

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

    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)));

    ?>

    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

    Example #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"));

    ?>

    The above example will output something similar to:

    foobar got one and two
foobar got foo and bar

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

    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

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    User Contributed Notes 4 notes

    up
    54
    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
    up
    37
    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);
    ?>
    up
    1
    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.
    up
    -2
    james at gogo dot co dot nz
    19 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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