(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
ob_list_handlers — List all output handlers in use
Questa funzione non contiene parametri.
This will return an array with the output handlers in use (if any).
If output_buffering is enabled
and no output_handler is set,
or no callback or null was passed to ob_start(),
"default output handler" is returned.
Enabling output_buffering
and setting an output_handler
is equivalent to passing
an internal (built-in) function
to ob_start().
If a callable was passed to ob_start(),
the fully qualified name
of the callable is returned.
If the callable is an object implementing
__invoke(),
the fully qualified name
of the object's __invoke()
method is returned.
If the callable is a Closure,
"Closure::__invoke" is returned.
Example #1 ob_list_handlers() example
<?php
// using output_buffering=On, no output_handler set
var_dump(ob_list_handlers());
ob_end_flush();
// no callback or null
ob_start();
var_dump(ob_list_handlers());
ob_end_flush();
// anonymous function
ob_start(function($string) { return $string; });
var_dump(ob_list_handlers());
ob_end_flush();
// arrow function
ob_start(fn($string) => $string);
var_dump(ob_list_handlers());
ob_end_flush();
// first class callable
$firstClassCallable = userDefinedFunction(...);
ob_start([$firstClassCallable, '__invoke']);
var_dump(ob_list_handlers());
ob_end_flush();
// internal (built-in) function
ob_start('print_r');
var_dump(ob_list_handlers());
ob_end_flush();
// user-defined function
function userDefinedFunction($string, $flags) { return $string; };
ob_start('userDefinedFunction');
var_dump(ob_list_handlers());
ob_end_flush();
class MyClass {
public static function staticHandle($string) {
return $string;
}
public static function handle($string) {
return $string;
}
public function __invoke($string) {
return $string;
}
}
// class and static method
ob_start(['MyClass','staticHandle']);
var_dump(ob_list_handlers());
ob_end_flush();
// object and non-static method
ob_start([new MyClass,'handle']);
var_dump(ob_list_handlers());
ob_end_flush();
// invokable object
ob_start(new MyClass);
var_dump(ob_list_handlers());
ob_end_flush();
?>Il precedente esempio visualizzerà:
array(1) {
[0]=>
string(22) "default output handler"
}
array(1) {
[0]=>
string(22) "default output handler"
}
array(1) {
[0]=>
string(7) "print_r"
}
array(1) {
[0]=>
string(19) "userDefinedFunction"
}
array(1) {
[0]=>
string(17) "Closure::__invoke"
}
array(1) {
[0]=>
string(17) "Closure::__invoke"
}
array(1) {
[0]=>
string(17) "Closure::__invoke"
}
array(1) {
[0]=>
string(21) "MyClass::staticHandle"
}
array(1) {
[0]=>
string(15) "MyClass::handle"
}
array(1) {
[0]=>
string(17) "MyClass::__invoke"
}