[Development] Work on qDebug and friends - debug areas

[Lincoln Ramsay]

On 01/24/2012 09:03 PM, ext kai.koehne at nokia.com wrote:
> One of the things still missing in the current debugging framework is
> to categorize messages by area: This would allow you to
> enable/disable e.g. debug messages for only one part of your app ...
...
> That's at least what I got after doing 10 minutes of research :)
> Question is whether we want to have any of the approaches (or both)
> in QtCore?

Another data point...

The qLog approach (from Qtopia) uses macros to turn "strings" into 
classnames.

something like...

DECLARE_CATEGORY(x)

expanding to

class QLog_Category_x ...

Then qLog(x) expanded to
if (!QLog_Category_x::enabled()); QLog_Category_x::debug()


I guess the primary downside with this is the need to either centrally 
locate the declarations or duplicate the declarations in every .cpp file 
that needs them.

However, this gives you string-based categories without the cost of 
string comparisons and I suspect the size cost of the logging messages 
is larger than the cost of the category classes.


-- 
Lincoln Ramsay - Senior Software Engineer
Qt Development Frameworks, Nokia - http://qt.nokia.com/