PHP is_callable() Function

Check whether the contents of a variable can be called as a function or not:

<?php
function test1(){
}

echo "test1 is callable: " . is_callable("test1");
echo "<br>";
echo "test2 is callable: " . is_callable("test2");
?>

Definition and Usage

The is_callable() function checks whether the contents of a variable can be called as a function or not.

This function returns true (1) if the variable is callable, otherwise it returns false/nothing.

is_callable( variable, syntax_only, name );

Parameter	Description
variable	Required. Specifies the variable to check
syntax_only	Optional. If set to TRUE, the function only verifies if variable is a function or method. It will reject variables that are not strings, or arrays without a valid structure to be used as a callback. Default is false
name	Optional. Returns a "callable name" (only for classes)

Return Value:	TRUE if variable is callable, FALSE otherwise
Return Type:	Boolean
PHP Version:	4.0.6+