call_user_func_array
create_function
Function handling Functions
PHP Manual

# call_user_func

(PHP 4, PHP 5)

call_user_func — Call the callback given by the first parameter

### Description

mixed call_user_func ( callable `$callback` [, mixed `$parameter` [, mixed `$...` ]] )

Calls the `callback` given by the first parameter and passes the remaining parameters as arguments.

### Parameters

`callback`

  The callable to be called.

`parameter`

  Zero or more parameters to be passed to the callback.

  > 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 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 #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

- call_user_func_array() - Call a callback with an array of parameters
- is_callable() - Verify that the contents of a variable can be called as a function
- information about the callback type
- ReflectionFunction::invoke() - Invokes function
- ReflectionMethod::invoke() - Invoke

call_user_func_array
create_function
Function handling Functions
PHP Manual