is_callable

is_callable

Verify that a value can be called as a function from the current scope

bool **is_callable** mixed $value bool $syntax_only string $callable_name

Verifies that is a , or that it can be called using the function. value``callable``call_user_func

valueThe value to be checked.

syntax_only If set to true the function only verifies that might be a function or method. It will reject any values that are not objects, , strings, or arrays that do not have a valid structure to be used as a callback. A valid callable array has 2 entries, the first of which is an object or a string, and the second a string. valueinvokableClosure

callable_name Receives the "callable name", e.g. . Note, however, that despite the implication that is a callable static method, this is not the case. "SomeClass::someMethod"``SomeClass::someMethod()

Returns true if is callable, false otherwise. value

Voorbeeld: Checking whether a string can be called as a function

<?php

function someFunction() {}

$functionVariable = 'someFunction';

var_dump(is_callable($functionVariable, false, $callable_name));

var_dump($callable_name);

?>

bool(true)
string(12) "someFunction"

Voorbeeld: Checking whether an array can be called as a function

<?php

class SomeClass
{
    public function someMethod() {}
}

$anObject = new SomeClass();

$methodVariable = [$anObject, 'someMethod'];

var_dump(is_callable($methodVariable, true, $callable_name));

var_dump($callable_name);

?>

bool(true)
string(21) "SomeClass::someMethod"

Voorbeeld: and constructors

 Despite the fact that constructors are the methods that are called when
 an object is created, they are not static methods and
  will return false for them. It's not
 possible to use  to check if a class can
 be instantiated from the current scope.
`is_callable``is_callable`

<?php

class Foo
{
    public function __construct() {}

    public function foo() {}
}

var_dump(
    is_callable(['Foo', '__construct']),
    is_callable(['Foo', 'foo'])
);

$foo = new Foo();
var_dump(is_callable([$foo, '__construct']));

?>

bool(false)
bool(false)
bool(true)

__invoke()__callStatic()__call()

call_user_func``function_exists``method_exists