Podręcznik PHP
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# is_callable

(PHP 4 >= 4.0.6)

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

## Description

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.

The `var` parameter 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')

If the `syntax_only` argument is `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.

The `callable_name` argument receives the "callable name". In the example below it's "someClass:someMethod". Note, however, that despite the implication that someClass::SomeMethod() is a callable static method, this is not the case.

`<?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 ?>`

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is_bool | Początek rozdziału | is_double