On 28.12.2017, at 22:09, Fabio Niephaus lists@fniephaus.com wrote:

Hi all,

SmalltalkImage>>processShutDownList: sends #shutdown: to all classes in ShutDownList, yet there are classes that don't implement #shutdown: but #shutdown. One example is ExternalSettings class>>shutDown, ExternalSettings is in ShutDownList. Can someone explain how this is supposed to work or why there is no error when the image is shutting down?

Behavior>>shutDown: quitting "This message is sent on system shutdown to registered classes" ^self shutDown.

Best -Tobi

Best, Fabio

On Thu, 28 Dec 2017, Fabio Niephaus wrote:

Hi all, SmalltalkImage>>processShutDownList: sends #shutdown: to all classes in ShutDownList, yet there are classes that don't implement #shutdown: but #shutdown. One example is ExternalSettings class>>shutDown, ExternalSettings is in ShutDownList. Can someone explain how this is supposed to work or why there is no error when the image is shutting down?

It may be tempting to implement #shutDown when you don't need the argument, but I suggest you should not use it, ever. Why? Because if someone implements #shutDown: in a superclass of yours, your #shutDown method will (probably) not be sent, and tracking down such bugs is rather time consuming.

Same applies to #startUp.

Also, the argument is useful in almost all cases, it's just that people probably forgot to use it. That alone gives about a second overhead to image saving. So, please use the argument.

Actually both #shutDown and #startUp should be deprecated some way.

Levente

Best, Fabio