[LAD] Session Handlers and 'level 1' support

[Nedko Arnaudov]

Chris Cannam <cannam at all-day-breakfast.com> writes:

> On Fri, Jan 8, 2010 at 11:00 AM, Nedko Arnaudov <nedko at arnaudov.name> wrote:
>> Chris Cannam <cannam at all-day-breakfast.com> writes:
>>> What I mean is: if the user starts an application that has no
>>> knowledge of LADI at all, and they check the level 1 box in ladish, is
>>> that application then guaranteed to crash on session save and lose
>>> their data because of an unhandled signal?
>>
>> If user checks level 1 in ladish when starting the app, then ladish will
>> send SIGUSR1 to the app. If the app actually does not support level 1,
>> signal will be sent and chances are that default signal handler will be
>> executed. The default signal handler is to terminate the app.
>
> That sounds rather hazardous to me.  To lose all of one's data instead
> of saving it, after a potentially long session's work, because of a
> check box incorrectly checked when starting the session, surely
> wouldn't please many users?

Please take a look at the video. You are wrong. The radio button is
selected when app is started for first time, not when "session" is
started.

>> Applications cannot register themself yet.
>
> I think I must have misunderstood the use of D-BUS here, then.  I had
> thought that LADI was a D-BUS service which the application connected
> to, so that LADI would know whether an application was running in a
> "LADI-aware" state or not.

This is a myth. I've explained what D-Bus usage in ladish (and LASH) is
in a recent mail to this mailing list.

-- 
Nedko Arnaudov <GnuPG KeyID: DE1716B0>
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