[Development] QLog ( Work on qDebug and friends)

David Faure david.faure at kdab.com
Tue Feb 21 11:28:56 CET 2012

On Tuesday 21 February 2012 10:21:29 lorn.potter at nokia.com wrote:
> On 21/02/2012, at 7:36 PM, ext David Faure wrote:
> > On Tuesday 21 February 2012 06:28:38 wolfgang.beck at nokia.com wrote:
> >> I'm preferring having QLog active only if a config file is there.
> >> It doesn't make sense to me at all having an environment variable that
> >> can
> >> activate QLog but not config file to activate the categories. As long
> >> there
> >> is no config file QLog is disable and uses less performance as possible
> >> but
> >> still having the feature that you can activate it without recompiling the
> >> code.
> > 
> > Why? IMHO things should go to stderr by default. So it makes perfect sense
> > to see the output, even if one didn't configure output files in a config
> > file.
> The whole idea is to have noop by default. Nothing. Ziltch. Not even std
> err. Use qWarning if you want or need that. That's what it's for. If you
> need this, only when you do a magical incantation, such as a config file or
> env var, will it produce any output.

I agree.
However my point was: once turned on, it could just go to stderr, and not 
require configuration of an output file.

> > I guess this is a mobile platform vs desktop platform discussion. On a
> > mobile platform the logs are only useful if they go to a file, while on
> > the desktop the logs are useful also if they go to stderr, to get them in
> > a terminal or in the session log file.
> Not really. It's more of not wanting to have any performance hits in
> shipping code. Even on embedded systems, developers want and need console
> output, and support services might need detailed log file at times. qlog
> makes this possible. Nothing stopping anyone from doing a tail -f my.log

But there won't be a "my.log" configured by default, so the user needs to set 
that up first.
I'm aiming at something that is simple to use for the simple case. When a user 
comes on IRC with a bug and we want to see the output, it should be simple for 
him/her to get that output. Finding the right config file and editing it by hand 
isn't exactly simple. Well, OK, a GUI tool can fix that; maybe we can even make 
that part of qtconfig. That would fix the issue nicely, in fact.

OK, so objections withdrawn.

David Faure | david.faure at kdab.com | KDE/Qt Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, Sweden (HQ) +46-563-540090
KDAB - Qt Experts - Platform-independent software solutions

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