GoLang is_callable

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PHP is_callable

PHP original manual for is_callable [ show | php.net ]


(PHP 4 >= 4.0.6, PHP 5, PHP 7)

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


bool is_callable ( mixed $var [, bool $syntax_only = FALSE [, string &$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.



The value to check


If set to TRUE the function only verifies that name 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.


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.

Return Values

Returns TRUE if var is callable, FALSE otherwise.


Example #1 is_callable() example

//  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 {



$anObject = new someClass();

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

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

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


Example #2 is_callable() and constructors

As of PHP 5.3.0 is_callable() reports constructors as not being callable. This affects PHP 5 style constructors (__construct) as well as PHP 4 style constructors (i.e. methods with the same name as the class). Formerly, both cases have been considered callable.


class Foo
    public function 
__construct() {}
    public function 
foo() {}


The above example will output:


See Also