call_user_func

(PHP 4, PHP 5)

call_user_func — 传入一个参数来调用回调函数

说明

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

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

参数

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";
?>

以上例程会输出：

0
1

返回值

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

范例

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");
?>

以上例程会输出：

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

?>

以上例程会输出：

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'));

?>

以上例程会输出：

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 */
?>

以上例程会输出：

[test]

call_user_func_array

(PHP 4 >= 4.0.4, PHP 5)

call_user_func_array — 传入一个参数数组来调用回调函数

说明

mixed call_user_func_array ( callable $callback , array $param_arr )

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

参数

callback: The callable to be called.
param_arr: The parameters to be passed to the callback, as an indexed array.

返回值

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

范例

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"));
?>

以上例程的输出类似于：

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'));

?>

以上例程的输出类似于：

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 */

?>

以上例程会输出：

int(8)

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