call_user_func
(PHP 4, PHP 5)
call_user_func — Call a user function given by the first parameter
说明
mixed call_user_func ( callback $function [, mixed $parameter [, mixed $... ]] )Call a user defined function given by the function parameter.
参数
- function
-
The function to be called. Class methods may also be invoked statically using this function by passing array($classname, $methodname) to this parameter. Additionally class methods of an object instance may be called by passing array($objectinstance, $methodname) to this parameter.
- parameter
-
Zero or more parameters to be passed to the function.
Note:
Note that the parameters for call_user_func() are not passed by reference.
Example #1 call_user_func() example and references
<?php
error_reporting(E_ALL);
function increment(&$var)
{
$var++;
}
$a = 0;
call_user_func('increment', $a);
echo $a." ";
call_user_func_array('increment', array(&$a)); // You can use this instead before PHP 5.3
echo $a." ";
?>以上例程会输出：
0 1
返回值
Returns the function result, or FALSE on error.
更新日志
| 版本 | 说明 |
|---|---|
| 5.3.0 | The interpretation of object oriented keywords like parent and self has changed. Previously, calling them using the double colon syntax would emit an E_STRICT warning because they were interpreted as static. |
范例
Example #2 call_user_func() example 以上例程会输出： Example #3 call_user_func() using namespace name 以上例程会输出： Example #4 Using a class method with call_user_func() 以上例程会输出： Example #5 Using lambda function with call_user_func() 以上例程会输出：
<?php
function barber($type)
{
echo "You wanted a $type haircut, no problem
";
}
call_user_func('barber', "mushroom");
call_user_func('barber', "shave");
?>
You wanted a mushroom haircut, no problem
You wanted a shave haircut, no problem
<?php
namespace Foobar;
class Foo {
static public function test() {
print "Hello world!
";
}
}
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
?>
Hello world!
Hello world!
<?php
class myclass {
static function say_hello()
{
echo "Hello!
";
}
}
$classname = "myclass";
call_user_func(array($classname, 'say_hello'));
call_user_func($classname .'::say_hello'); // As of 5.2.3
$myobject = new myclass();
call_user_func(array($myobject, 'say_hello'));
?>
Hello!
Hello!
Hello!
<?php
call_user_func(function($arg) { print "[$arg]
"; }, 'test');
?>
[test]
注释
Note:
在函数中注册有多个回调内容时(如使用 call_user_func() 与 call_user_func_array())，如在前一个回调中有未捕获的异常，其后的将不再被调用。
参见
- call_user_func_array() - Call a user function given with an array of parameters
- is_callable() - 检测参数是否为合法的可调用结构
- callback 类型的信息
