is_callable

(PHP 4 >= 4.0.6, PHP 5)

is_callable — Verify that the contents of a variable can be called as a function

Описание

bool is_callable ( mixed $var [, bool $syntax_only [, string &$callable_name ]] )

Verify that the contents of a variable can be called as a function. This can check that a simple variable contains the name of a valid function, or that an array contains a properly encoded object and function name.

Список параметров

var

Can be either the name of a function stored in a string variable, or an object and the name of a method within the object, like this:

array($SomeObject, 'MethodName')

syntax_only

If set to TRUE the function only verifies that var might be a function or method. It will only reject simple variables that are not strings, or an array that does not have a valid structure to be used as a callback. The valid ones are supposed to have only 2 entries, the first of which is an object or a string, and the second a string.

callable_name

Receives the "callable name". In the example below it is "someClass::someMethod". Note, however, that despite the implication that someClass::SomeMethod() is a callable static method, this is not the case.

Возвращаемые значения

Returns TRUE if var is callable, FALSE otherwise.

Примеры

Пример #1 is_callable() example

<?php
//  How to check a variable to see if it can be called
//  as a function.

//
//  Simple variable containing a function
//

function someFunction() 
{
}

$functionVariable 'someFunction';

var_dump(is_callable($functionVariablefalse$callable_name));  // bool(true)

echo $callable_name"\n";  // someFunction

//
//  Array containing a method
//

class someClass {

  function 
someMethod() 
  {
  }

}

$anObject = new someClass();

$methodVariable = array($anObject'someMethod');

var_dump(is_callable($methodVariabletrue$callable_name));  //  bool(true)

echo $callable_name"\n";  //  someClass::someMethod

?>

Смотрите также

Коментарии

If the target class has __call() magic function implemented, then is_callable will ALWAYS return TRUE for whatever method you call it.
is_callable does not evaluate your internal logic inside __call() implementation (and this is for good).
Therefore every method name is callable for such classes.

Hence it is WRONG to say (as someone said):
...is_callable will correctly determine the existence of methods made with __call...

Example:
<?php
class TestCallable
{
    public function 
testing()
    {
          return 
"I am called.";
    }

    public function 
__call($name$args)
    {
        if(
$name == 'testingOther'
        {
                return 
call_user_func_array(array($this'testing'), $args);
        }
    }
}

$t = new TestCallable();
echo 
$t->testing();      // Output: I am called.
echo $t->testingOther(); // Output: I am called.
echo $t->working();      // Output: (null)

echo is_callable(array($t'testing'));       // Output: TRUE
echo is_callable(array($t'testingOther'));  // Output: TRUE
echo is_callable(array($t'working'));       // Output: TRUE, expected: FALSE
?>
2016-01-11 08:50:19
http://php5.kiev.ua/manual/ru/function.is-callable.html
Note that -- as mentioned in the migration guide-- starting from PHP 8.0, is_callable() will not work with non-static methods if you use a class name, instead an object of the class should be provided:

<?php

class Test
{
    public function 
method1() { }
    public static function 
method2() { }
}

// Pre PHP 8
var_dump(is_callable(array('Test''method1'))); // bool(true)
var_dump(is_callable(array('Test''method2'))); // bool(true)

// Post PHP 8
var_dump(is_callable(array('Test''method1'))); // bool(false)
var_dump(is_callable(array('Test''method2'))); // bool(true)
var_dump(is_callable(array(new Test'method1'))); // bool(true)

?>
2021-06-28 15:26:25
http://php5.kiev.ua/manual/ru/function.is-callable.html

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