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Register a function for execution on shutdown
Function handling Functions
PHP Manual


(PHP 4, PHP 5)

register_shutdown_functionRegister a function for execution on shutdown


void register_shutdown_function ( callable $callback [, mixed $parameter [, mixed $... ]] )

Registers a callback to be executed after script execution finishes or exit() is called.

Multiple calls to register_shutdown_function() can be made, and each will be called in the same order as they were registered. If you call exit() within one registered shutdown function, processing will stop completely and no other registered shutdown functions will be called.



The shutdown callback to register.

The shutdown callbacks are executed as the part of the request, so it's possible to send output from them and access output buffers.


It is possible to pass parameters to the shutdown function by passing additional parameters.


Return Values

No value is returned.


If the passed callback is not callable a E_WARNING level error will be generated.


Version Description
4.1.0 The shutdown functions are now called as a part of the request. In earlier versions under Apache, the registered shutdown functions were called after the request has been completed (including sending any output buffers), so it was not possible to send output to the browser using echo or print, or retrieve the contents of any output buffers using ob_get_contents(). Headers were also always already sent.


Example #1 register_shutdown_function() example

function shutdown()
// This is our shutdown function, in 
    // here we can do any last operations
    // before the script is complete.

echo 'Script executed with success'PHP_EOL;




Working directory of the script can change inside the shutdown function under some web servers, e.g. Apache.


Shutdown functions will not be executed if the process is killed with a SIGTERM or SIGKILL signal. While you cannot intercept a SIGKILL, you can use pcntl_signal() to install a handler for a SIGTERM which uses exit() to end cleanly.

See Also

Function handling Functions
PHP Manual