(PHP 4 >= 4.0.4, PHP 5, PHP 7)
call_user_func_array — Call a callback with an array of parameters
Calls the callback given by the first parameter with
the parameters in param_arr.
callbackThe callable to be called.
param_arrThe parameters to be passed to the callback, as an indexed array.
Returns the return value of the callback, or FALSE on error.
| 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.
|
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)
Note:
Before PHP 5.4, referenced variables in
param_arrare 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() returnFALSE(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.
Just hope this note helps someone (I killed the whole day on issue).
If you use something like this in PHP < 5.3:
<?php call_user_func_array(array($this, 'parent::func'), $args); ?>
Such a script will cause segmentation fault in your webserver.
In 5.3 you should write it:
<?php call_user_func_array('parent::func', $args); ?>
Please note, that when calling call_user_func_array() to redirect parameters between inherited classes, you should not use $this, because $this always refers to the class which has been instantiated. The following code even seems to crash PHP (PHP does not report error but the process simply terminates), because the the parameters are redirected only one level up (to class foo_bar2):
<?php
class foo_bar1
{
public function __construct()
{
echo __CLASS__ . PHP_EOL;
if (func_num_args() > 0)
{
$constructorArgs = func_get_args();
call_user_func_array(array($this, 'parent::__construct'), $constructorArgs);
}
else
{
parent::__construct();
}
}
}
class foo_bar2 extends foo_bar1
{
public function __construct()
{
echo __CLASS__ . PHP_EOL;
if (func_num_args() > 0)
{
$constructorArgs = func_get_args();
call_user_func_array(array($this, 'parent::__construct'), $constructorArgs);
}
else
{
parent::__construct();
}
}
}
class foo_bar3 extends foo_bar2
{
public function __construct()
{
echo __CLASS__ . PHP_EOL;
if (func_num_args() > 0)
{
$constructorArgs = func_get_args();
call_user_func_array(array($this, 'parent::__construct'), $constructorArgs);
}
else
{
parent::__construct();
}
}
}
$f = new foo_bar3("abc");
?>
Instead, use the direct name of the class as string or, better, the magic constant __CLASS__ in call_user_func_array(), like:
call_user_func_array(array(__CLASS__, 'parent::__construct'), $constructorArgs);
Then the parameters will be correctly redirected to the lowest base class.
$param_arr may be empty, though it can't be null.
<?php
function foo( $first = 'default1', $second = 'default2' ) {
echo "first: '$first', second: '$second'\n";
}
call_user_func_array( 'foo', array( 'one', 'two' ) );
call_user_func_array( 'foo', array( 'only one' ) );
call_user_func_array( 'foo', array() );
call_user_func_array( 'foo', null );
?>
Output:
first: 'one', second: 'two'
first: 'only one', second: 'default2'
first: 'default1', second: 'default2'
/* error message or nothing printed depending on version */
As of PHP 5.6 you can utilize argument unpacking as an alternative to call_user_func_array, and is often 3 to 4 times faster.
<?php
function foo ($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
For anyone looking for the means to test for the first parameter before passing to this function, look at the is_callable (http://php.net/manual/en/function.is-callable.php) variable handler.
<?php
$handler = array( 'MyClass', 'MyMethod');
$params = array(1,2,3,4);
if ( is_callable($handler) ) { call_user_func_array( $handler , $params ); }
?>
Those having the passing by reference issue can use this simple hack.
I´m really not sure WHY this works, but it does, and it does not make use of EVAL or other questionable functions.
<?php
function executeHook($name, $type='hooks'){
$args = func_get_args();
array_shift($args);
array_shift($args);
//Rather stupid Hack for the call_user_func_array();
$Args = array();
foreach($args as $k => &$arg){
$Args[$k] = &$arg;
}
//End Hack
$hooks = &$this->$type;
if(!isset($hooks[$name])) return false;
$hook = $hooks[$name];
call_user_func_array($hook, $Args);
}
?>
All it´s doing is copying the args ($args) into a new array ($Args) by reference, which i would think would be identical to the original array in every way (that matters).
Note the code here is an example of usage. The actual hack is denoted by comments.
If someone knows a better alternative, by all means, i would love to see it.
For those wishing to implement call-by-name functionality in PHP, such as implemented e.g. in DB apis, here's a quick-n-dirty version for PHP 5 and up
<?php
/**
* Call a user function using named instead of positional parameters.
* If some of the named parameters are not present in the original function, they
* will be silently discarded.
* Does no special processing for call-by-ref functions...
* @param string $function name of function to be called
* @param array $params array containing parameters to be passed to the function using their name (ie array key)
*/
function call_user_func_named($function, $params)
{
// make sure we do not throw exception if function not found: raise error instead...
// (oh boy, we do like php 4 better than 5, don't we...)
if (!function_exists($function))
{
trigger_error('call to unexisting function '.$function, E_USER_ERROR);
return NULL;
}
$reflect = new ReflectionFunction($function);
$real_params = array();
foreach ($reflect->getParameters() as $i => $param)
{
$pname = $param->getName();
if ($param->isPassedByReference())
{
/// @todo shall we raise some warning?
}
if (array_key_exists($pname, $params))
{
$real_params[] = $params[$pname];
}
else if ($param->isDefaultValueAvailable()) {
$real_params[] = $param->getDefaultValue();
}
else
{
// missing required parameter: mark an error and exit
//return new Exception('call to '.$function.' missing parameter nr. '.$i+1);
trigger_error(sprintf('call to %s missing parameter nr. %d', $function, $i+1), E_USER_ERROR);
return NULL;
}
}
return call_user_func_array($function, $real_params);
}
?>
Just a heads up, the second parameter MUST be an array if it's specified, but that doesn't seem to be enforced until ~5.3.
I just pulled my hair out with an old installation of CakePHP because it was passing NULL instead of an empty array.
call_user_func_array can pass parameters as reference:
<?php
call_user_func_array(array(&$obj,$method),array(&$arg1,$arg2,$arg3))
?>
Use it as work-around for "Call-time pass-by-reference has been deprecated".
Many people have wondered how to effectively implement dispatch tables in PHP. Here's my answer to that (if you'll forgive my creative flair):
<?php
/*
* Using dispatch tables in PHP.
*
* --Kris Craig
*/
define( "YOUR_MOTHER", 1 );
define( "YOUR_FATHER", 2 );
define( "YOUR_BROTHER", 3 );
define( "YOUR_SISTER", 4 );
class MyFamily
{
static $dispatch = array( YOUR_MOTHER => "Mom", YOUR_FATHER => "GetPrisonInmate", YOUR_BROTHER => "ReplaceName", YOUR_SISTER => "LazyGirl" );
static $args = array( YOUR_MOTHER => array(), YOUR_FATHER => array( "55170-054", TRUE ), YOUR_BROTHER => array(), YOUR_SISTER => array() );
function GetDispatch( $fromwhere )
{
return call_user_func_array( array( self, self::$dispatch[$fromwhere] ), self::$args[$fromwhere] );
}
function Mom()
{
return "Mommy loves you!";
}
function GetPrisonInmate( $PrisonerID, $GoodBehavior )
{
//Check prison records for his ID, then....
if ( $GoodBehavior )
{
$parole = "APPROVED";
}
else
{
$parole = "DENIED";
}
return "Your father (#$PrisonerID) has $remaining years left in his sentence. His most recent parole application has been: $parole";
}
function ReplaceName()
{
return "Her name is Sally now.";
}
function LazyGirl()
{
print "Your sister needs to get out more....";
//sleep( pow( 60, 2 ) * 18 ); //You can sleep later!
die( "Nah, I'm too tired." );
}
}
print "Status on family member: " . MyFamily::GetDispatch( YOUR_FATHER );
?>
It appears that when PHP executes something like:
$a = array(1,2,3);
$b =& $a[1];
both $b and $a[1] are converted into references to a common value -- makes sense until you transfer that to a call_user_func:
call_user_func_array('foo', $a);
suddenly, inside foo, the second parameter is passed by reference!
And you can't call this wrong, only another subtly of references.
Note it appears that ksort($a) will remove the reference as well as put the elements in key order so you (probably) get what you expect. (see below on the use of a foreach ($a as &v).)
There's a possibility that call_user_func_array(), call_user_func(), and Exception::getTrace() will cause a trace entry to not have the 'file' or 'line' elements.
Dustin Oprea
Regarding the comments below about calling parent constructors:
PHP5 with E_STRICT no longer allows calls as below:
<?php
// Causes an error with E_STRICT
call_user_func_array(array('parent', '__construct'), $args);
?>
It gives an error because you are trying to call a nonstatic function as if it was static. The correct syntax is
<?php
// Works fine
call_user_func_array(array($this, 'parent::__construct'), $args);
?>
Just an extra for the post of amer at o2 dot pl:
If you need to call the PARENT method:
call_user_func_array(array('parent', 'method'), $args);
With that, if you need to call a constructor and/or add some extra code to the instantiation process:
<?php
function __construct() {
// Get the arguments
$args = func_get_args();
// Initialize parent with arguments
call_user_func_array(array('parent', '__construct'), $args);
// ... Your Code Here ...
}
?>
Note that your constructor pass all the arguments to the parent constructor and it doesn't matter how many arguments you pass.
This is pretty useful for constructors with a variable number of arguments.
I've found the solution to resolve my need while writing the str_replace function for processing the multi array as first two arguments of str_replace built-in function(although its pass each array of argument 1 & 2)
<?php
// custom the str_replace function
function p_str_replace($argFind, $agrReplace, $theString) {
$needle_replace = $theString; // handle the string need to be replace
array_walk($argFind, function($val, $key) use(&$needle_replace, $agrReplace) {
$needle_replace = call_user_func_array('str_replace', array($val, $agrReplace[$key], $needle_replace));
});
return $needle_replace;
}
// test
$the_str = array(
'coa' => ':col: :op1: :val: AND :col: :op2: :val:'
);
$ope = array('>=', '<=');
$colsdata = array('date_start', '2015-10-14');
echo p_str_replace(array(
array(':col:', ':val:'),
array(':op1:', ':op2:')
), array(
$colsdata,
$ope
), $the_str['coa']);
echo '-------------------------------' . "\n";
// more complexity
$complex = '(:col: :op1: :val: AND :col: :op2: :val:) AND (:col2: :op1: :val2: AND :col2: :op1: :val2:)';
echo p_str_replace(array(
array(':col:', ':val:'),
array(':col2:', ':val2:'),
array(':op1:', ':op2:')
), array(
array('date_start', '2015-10-01'),
array('date_end', '2015-10-14'),
array('>', '<')
), $complex);
?>
Sorry about my bad English :)
Hope this help someone.
PLS notice that "patripaq at hotmail dot com" 's code will be valid if B EXTENDS A...
<?php
class B extends A{
...
}
?>
there>>"What I wanted to do is create an object that can manage any number and any kind of parameters."
BUT IT IS NOT A POINT AT ALL
If you need to call just function with parameters:
call_user_func_array('Foo',$args);
If you need to call CLASS method (NOT object):
call_user_func_array(array('class', 'Foo'),$args);
If you need to call OBJECT method:
call_user_func_array(array(&$Object, 'Foo'),$args);
If you need to call method of object of object:
call_user_func_array(array(&$Object->Object, 'Foo'),$args);
If you need to call object method from within the very same object (NOT CLASS!):
call_user_func_array(array(&$this, 'Foo'),args);
The call_user_func_array ITSELF can manage any number and any kind of parameters. It can handle ANY FUNCTION too as it is defined and that maybe partipaq wanted to manage.
What You actually need is object composition not inheritance. Make an instance from arguments.
<?php
...
class B{
function __construct() {
$args = func_get_args(); // Get arguments
$this->OBJ = new A($args);
call_user_func_array(array(&$this->OBJ, 'A'), $args );
}
}
?>
Then there can be any number and any type of created object B parameters
For those of you that have to consider performance: it takes about 3 times as long to call the function this way than via a straight statement, so whenever it is feasible to avoid this method it's a wise idea to do so.
Note that eval() is about 10 times slower than a straight statement to call a function with arguments, so this is definitely a better option than using eval() even if you only consider performance.
call_user_func_array() is nifty for calling PHP functions which use variable argument length. For example:
<?php
$array = array(
array("foo", "bar"),
array("bat", "rat"),
);
$values = call_user_func_array("array_merge", $array);
var_dump($values);
?>
/* output:
array(4) {
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "bat"
[3]=>
string(3) "rat"
}
*/
The neat feature is that $array could have any number of arrays inside it.
<?php
Class Delegate
{
private $arrInstances = array();
protected function addObject( $oElement )
{
// add one element on the end of the stack //
$this->arrInstances[] = $oElement;
}
public function __call( $strMethod, $arrParams )
{
// for each element in instance //
foreach( $this->arrInstances as $oElement )
{
// get the class of the element //
$strClass = get_class( $oElement );
// get all methods of the class //
$arrMethods = get_class_methods( $strClass );
// case the method exists into this class //
if( in_array( $strMethod , $arrMethods ) )
{
// prepare caller //
$arrCaller = Array( $strClass , $strMethod );
// return the result of the method into the object //
return call_user_func_array( $arrCaller, $arrParams );
}
}
// any object has the method //
// throw a exception //
throw new Exception( " Method " . $strMethod . " not exist in this class " . get_class( $this ) . "." );
}
}
class Log
{
public function sayHi()
{
print "hi!" . "<br/>\n";
}
public function sayMyName()
{
print "log" . "<br/>\n";
}
}
class Other
{
public function sayHello()
{
print "hello there!" . "<br/>\n";
}
public function sayMyName()
{
print "other" . "<br/>\n";
}
}
class Example extends Delegate
{
public function __construct()
{
$this->addObject( new Log() );
$this->addObject( new Other() );
}
}
$oExample = new Example();
$oExample->sayHi();
$oExample->sayHello();
$oExample->sayMyName();
/*
hi!<br/>
hello there!<br/>
log<br/>
*/
?>
Be aware the call_user_func_array always returns by value, as demonstrated here...
<?php
function &foo(&$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;
}
?>
If you are using PHP < 5.3 and want to call the parent class' __construct() with a variable parameter list, use this:
<?php
public function __construct()
{
$vArgs = func_get_args(); // you can't just put func_get_args() into a function as a parameter
call_user_func_array(array('parent', '__construct'), $vArgs);
}
?>
This function is relatively slow (as of PHP 5.3.3) and if you are calling a method with a known number of parameters it is much faster to call it this way:
$class->{$method}($param1, $param2);
vs
call_user_func_array (array($class, $method), array($param1, $param2));
But if you don't know how many parameters...
The wrapper function below is slightly faster, but the problem now is that you are making two function calls. One to the wrapper and one to the function.
However, If you are able to take this code out of the function and use it inline it is nearly twice as fast (in most cases) as calling call_user_func_array natively.
<?php
function wrap_call_user_func_array($c, $a, $p) {
switch(count($p)) {
case 0: $c->{$a}(); break;
case 1: $c->{$a}($p[0]); break;
case 2: $c->{$a}($p[0], $p[1]); break;
case 3: $c->{$a}($p[0], $p[1], $p[2]); break;
case 4: $c->{$a}($p[0], $p[1], $p[2], $p[3]); break;
case 5: $c->{$a}($p[0], $p[1], $p[2], $p[3], $p[4]); break;
default: call_user_func_array(array($c, $a), $p); break;
}
}
?>
<?php
return call_user_func_array(
array(new ReflectionClass($className), 'newInstance'),
$functionParameters
);
?>
Look here: http://www.zend.com/zend/week/week182.php#Heading1
Note that, despite the name, this does work on builtin functions (and object methods with the array(&$obj, $method) syntax), not just user-defined functions and methods.
Here is another version of createObjArray() function written here earlier by taylor.
Believing that using 'eval()' is at least "dirty", I came to the following solution (with a help of panchous - at phpclub dot ru forums ). This solution utilizes the new Reflection API.
<?php
function & createObjArray($type, $args = array()) {
$reflection = new ReflectionClass($type);
$output = call_user_func_array(array(&$reflection, 'newInstance'), $args);
return $output;
}
?>
I came up with a better solution to the problem that I solve below with createObjArray that maintains parameter type:
<?php
function createObjArray($type,$args=array()) {
$paramstr = '';
for ($i = 0; $i < count($args); $i++) {
$paramstr .= '$args['.$i.'],';
}
$paramstr = rtrim($paramstr,',');
return eval("return new $type($paramstr);");
}
?>
Would be good to add error checking, but it works.
If you are thinking of using call_user_func_array to instantiate an object (see comments below using Reflection) then since v5.1.3 you can use the Reflection::newInstanceArgs() method.
<?php
// arguments you wish to pass to constructor of new object
$args = array('a', 'b');
// class name of new object
$className = 'myCommand';
// make a reflection object
$reflectionObj = new ReflectionClass($className);
// use Reflection to create a new instance, using the $args
$command = $reflectionObj->newInstanceArgs($args);
// this is the same as: new myCommand('a', 'b');
?>
I just noticed that when you use this function with parameters that need to be passed by reference it will not work.
<?php
function refFunc(&$var)
{
$var .= 'bar';
}
$var = 'foo';
?>
call_user_func_array('refFunc', array($var));
echo $var;
will output 'foo' and not 'foobar'. Witch is logical since you are declaring a new variable with array($var) however not so obvious.
