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is_callable
Verify that the contents of a variable can be called as a function
(PHP 4 >= 4.0.6, PHP 5)
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.
Parameters
- 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
TRUEthe 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.
Examples
Example 2590. 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()
{
}
$functionVariable = 'someFunction';
var_dump(is_callable($functionVariable, false, $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($methodVariable, true, $callable_name)); // bool(true)
echo $callable_name, "\n"; // someClass:someMethod
?>
| function_exists() |
| method_exists() |