Verify that the contents of a variable can be called as a function
Syntax
is_callable(mixed $value, bool $syntax_only = false, string &$callable_name = null): bool
Parameters
value
The value to check
syntax_only
If set to true the function only verifies that value 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".
Return
Returns true if value is callable, false otherwise.
Examples
1 · value · Function
<?
function myfunction()
{
}
$value = "myfunction";
$return = is_callable($value);
var_export($return);
?>
true
2 · value · Method
<?
class myclass
{
function myfunction()
{
}
}
$value = array(new myclass, "myfunction");
$return = is_callable($value);
var_export($return);
?>
true
3 · syntax_only · Function
<?
function myfunction()
{
}
$value = "myfunction";
$syntax_only = true;
$return = is_callable($value, $syntax_only);
var_export($return);
?>
true
4 · syntax_only · Method
<?
class myclass
{
function myfunction()
{
}
}
$value = array(new myclass, "myfunction");
$syntax_only = true;
$return = is_callable($value, $syntax_only);
var_export($return);
?>
true
5 · callable_name · Function
<?
function myfunction()
{
}
$value = "myfunction";
$syntax_only = true;
$return = is_callable($value, $syntax_only, $callable_name);
var_export($return);
echo PHP_EOL . $callable_name;
?>
true myfunction
6 · callable_name · Method
<?
class myclass
{
function myfunction()
{
}
}
$value = array(new myclass, "myfunction");
$syntax_only = true;
$return = is_callable($value, $syntax_only, $callable_name);
var_export($return);
echo PHP_EOL . $callable_name;
?>
true myclass::myfunction
