array ( 0 => 'index.php', 1 => 'PHP Manual', ), 'head' => array ( 0 => 'UTF-8', 1 => 'en', ), 'this' => array ( 0 => 'function.ob-list-handlers.php', 1 => 'ob_list_handlers', ), 'up' => array ( 0 => 'ref.outcontrol.php', 1 => 'Output Control Functions', ), 'prev' => array ( 0 => 'function.ob-implicit-flush.php', 1 => 'ob_implicit_flush', ), 'next' => array ( 0 => 'function.ob-start.php', 1 => 'ob_start', ), 'alternatives' => array ( ), 'source' => array ( 'lang' => 'en', 'path' => 'reference/outcontrol/functions/ob-list-handlers.xml', ), ); $setup["toc"] = $TOC; $setup["toc_deprecated"] = $TOC_DEPRECATED; $setup["parents"] = $PARENTS; manual_setup($setup); ?>
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
ob_list_handlers — List all output handlers in use
This function has no parameters.
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();
?>
The above example will output:
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" }