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From: ali@polya.Stanford.EDU (Ali T. Ozer)
Newsgroups: comp.sys.next
Subject: Re: Power-Off message to Apps
Message-ID: <12846@polya.Stanford.EDU>
Date: 17 Nov 89 07:46:43 GMT
References: <6694@portia.Stanford.EDU>
Reply-To: ali@Polya.Stanford.EDU (Ali T. Ozer)
Organization: .
Lines: 41

In article <6694@portia.Stanford.EDU> John Lynch writes:
>I may have missed this discussion earlier, but I was wondering if anyone
>knows what(if any) messages the Worskpace Manager sends to the running 
>applications when the user hits the power off switch.  From the alert panel
>that gets displayed and its statement that "all unsaved changes will be lost",
>one would get the impression that all the Manager does is kill all of the
>current processes.

When the user tries to log out or power off the machine, the Workspace Manager
sends a powerOffIn:andSave: method to all the apps started from the Workspace
Manager itself.  The default implementation of this method in Application
causes the appPowerOffIn:andSave: method to be called in the app's delegate
with the same arguments sent from the Workspace Manager.  The first argument
specifies the time remaining before the app will be killed, unless the app
quits on its own accord earlier.  The second argument specifies if the user
wants all files saved or not.  In 0.9, this argument would be YES or NO
depending how the user replied to the "Cancel / Save / Don't Save" panel.
In 1.0, this argument is always NO, indicating that the apps should not try 
to save unsaved documents (hence the Workspace's warning, "all unsaved changes
will be lost").

Anyway, despite that an app can take its time quitting, perhaps if it needs
to close some files and such.  If it needs more than the default time
provided, it can also ask for my time with the extendPowerOffBy: message,
just like in 0.9 (and 0.8). 

>I've heard that in 0.8, there was more support for saving changes on
>power off but that it was taken out for 0.9 and 1.0.  If this is true, does
>anyone know the rationale for the change?

Rather than having the user hit "Save" on the Logout panel and have all the 
apps try to save their files within a finite time, it's better to have the
user explicitly save the documents that need to be saved and not deal with
the documents that don't need to be saved.  It might very well be the case
that you don't want to save all the changes; only some of them.

And, as you can see from above, the apps do have time to clean up and tie
loose ends; hitting "Logout" doesn't cause the Workspace to immediately
blast away all the running apps. 

Ali