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List:       kde-devel
Subject:    Re: qt-exceptions -> performance improvements
From:       Pete Goodliffe <pete.goodliffe () pace ! co ! uk>
Date:       2000-10-13 9:01:12
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Florent Pillet wrote:
> So, what to do? How can we get this extra performance and reduced memory
> usage? It's too tempting to just recompile with -fno-exceptions, I did it
> here and it works just fine with the apps I use :-)

Unfortunately, exceptions *are* a necessity. Some programs may need to use
C++ libraries that make use of exceptions. And as has been shown before,
these exceptions may need to propagate through the Qt library, or at least
through some parts of it.

Compiling without exception support will cause all sorts of nightmares in 
the future. Having two separate builds will in the end just cause confusion.

As for multithreading, it is possible that having two libraries for this
would be less of a bad idea.

For example, an app I am writing needs decent threading support. If we can't
get the support in from a reasonably early beginning the temptation would be
never to add it at all, and to hack around the whole threading issue.

In the long run having a non-thread-non-exception build and a 
thread-exception build may bite us. The memory footprint of KDE2 will 
increase: we will see more mt and exception-using apps, so there will be
a greater mix of apps using both libraries at once. More swapping, less
usable application workspace, worse performance.

These aren't answers, I know, just issues. Sorry!

Pete

-- 
Pete Goodliffe, Senior Software Engineer
Pace Micro Technology plc                     Tel: +44 (0) 1223 518579
645 Newmarket Road                            Fax: +44 (0) 1223 518526
Cambridge, CB5 8PB, United Kingdom            WWW: http://www.pace.co.uk/
 
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