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PHP: is_callable() function

Description

The is_callable() function is used to test that the contents of a variable, whether it can be called as a function or not.

Version:

(PHP 4 and above)

Syntax:

is_callable(var_name, syntax_only, callable_name)

Parameters:

Name Description Required /
Optional
Type
var_name Either the name of a function stored in a string variable, or an object and the name of a method within the object. Required Mixed*
syntax_only If set to TRUE, the function only verifies if it is a function or a method. It rejects simple variables those are not strings and an array not having a valid structure. Optional Boolean
callable_name Receives a "callable name". This option is implemented only for classes. Optional String

*Mixed : Mixed indicates that a parameter may accept multiple (but not necessarily all) types.

Return value:

TRUE if var_name is callable, FALSE otherwise.

Value Type: Boolean.

Example :

<?php
function foo(){
}
echo is_callable('foo');
echo is_callable('bar');
?>

Output :

1

View the example in the browser

Practice here online :

See also

PHP Function Reference

Previous: is_bool
Next: is_double



PHP: Tips of the Day

SQL injection that gets around mysql_real_escape_string()

Consider the following query:

$iId = mysql_real_escape_string("1 OR 1=1");    
$sSql = "SELECT * FROM table WHERE id = $iId";

mysql_real_escape_string() will not protect you against this. The fact that you use single quotes (' ') around your variables inside your query is what protects you against this. The following is also an option:

$iId = (int)"1 OR 1=1";
$sSql = "SELECT * FROM table WHERE id = $iId";

Ref : https://bit.ly/32q3bJ7