is_callable
Description
The is_callable of Variable Handling for PHP 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
): boolParameters
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 = [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 = [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 = [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
Links
Variable Handling
- boolval
- debug_zval_dump
- doubleval
- empty
- floatval
- get_debug_type
- get_defined_vars
- get_resource_id
- get_resource_type
- gettype
- intval
- is_array
- is_bool
- is_countable
- is_double
- is_float
- is_int
- is_integer
- is_iterable
- is_long
- is_null
- is_numeric
- is_object
- is_real
- is_resource
- is_scalar
- is_string
- isset
- print_r
- serialize
- settype
- strval
- unserialize
- unset
- var_dump
- var_export
