call_user_func
(PHP 4, PHP 5)
call_user_func — Вызывает пользовательскую функцию
Описание
Вызывает пользовательскую функцию function со следующими параметрами:
<?php
function barber($type)
{
echo "You wanted a $type haircut, no problem";
}
call_user_func('barber', "mushroom");
call_user_func('barber', "shave");
?>
Методы класса также могут быть вызваны статически при передаче array($classname, $methodname) в качестве параметра function .
<?php
class myclass {
function say_hello()
{
echo "Hello!\n";
}
}
$classname = "myclass";
call_user_func(array($classname, 'say_hello'));
?>
Замечание: Обратите внимание, что параметры для call_user_func() не могут передаваться по ссылке.
<?php
function increment(&$var)
{
$var++;
}
$a = 0;
call_user_func('increment', $a);
echo $a; // 0
call_user_func_array('increment', array(&$a)); // You can use this instead
echo $a; // 1
?>
См. также: is_callable(), и call_user_func_array()
Коментарии
You don't need to use this function to call a variable class function. Instead you can do the following:
$this->{$fnname}();
The example works in PHP 5 from within the class. It is the {} that do the trick.
Regards,
Julian.
A good use for call_user_func(); is for recursive functions.
If you're distributing code, you will often come across users who will rename functions and break the code..
Use this: call_user_func(__FUNCTION__, ... ); inside a function to call itself with whatever parameters you want.
<?php
// example, an extremely simplified factorial calculator..
// it's quite obvious when someone renames the function, it'll spit out an error because it wants to call itself.
function Factorial($i=1) {
return($i==1?1:$i*Factorial($i-1));
}
// you can give this function whatever name you want, it'll always work, of course if you initially call it using the name you gave it.
function qwertyuiop($i=1) {
return($i==1?1:$i*call_user_func(__FUNCTION__,$i-1));
}
?>
Just that I didn't see any reference to recursive functions when user_call_func(); really helps.
if you simply want to dynamically call a method on an object it is not necessary to use call_user_function but instead you can do the following:
<?php
$method_name = "AMethodName";
$obj = new ClassName();
$obj->{$method_name}();
?>
I've used the above so I know it works.
Regards,
-- Greg
<?php
class MyClass{
public function hello($str)
{
echo 'hello ' . $str;
}
}
$obj = new MyClass();
[$obj, 'hello']('World'); // the array can be called as a function