[vlc-devel] KDE GUI platform

Rémi Denis-Courmont remi at remlab.net
Tue Feb 1 13:07:23 CET 2011


On Mon, 31 Jan 2011 22:46:10 +0100, Alex Fiestas <afiestas at kde.org> wrote:
>> For quite a while, the Qt4 open&  save file dialogs provided by the KDE
>> GUI platform plugin have been causing a segmentation fault at exit:
>> https://bugs.kde.org/show_bug.cgi?id=234484

> Well the thing is that there is not an effective way to work around this 
> bug, so the only thing we can do is remove the QProcess code from
> KFIleDialog, and if I remember correctly somebody is already working on 
> that or at least will work on it.

There is no way to work around this bug only if you assume that:
- QProcess is used, and
- QProcess is not fixed.

There are plenty of ways to work around it otherwise.

>> In any case, this is yet another bug in the KDE plugins for Qt. From
>> experience, the KDE project does not fix those bugs, as they only affect
>> Qt but non-KDE applications.
> We're willing to fix all bugs in our code, including those that only 
> affect Qt applications. Could you please elaborate a list of this kind 
> of bugs?

See above!

>> In this case, it's quite clear that Qt refuses to
>> implement the correct solution (see kde-core-devel).
> What would be the correct solution? as far as I know there is none.

There are several POSIX-portable ways to be notified of child process exit
while not interfering with signal handlers. It's not completely
straightforward but it is doable.

However, from what I read, Thiago Maceira is adamant that he does not want
Qt to implement any of that. Well, with the assumption that Qt remains
buggy then there are no correct solutions indeed.

Still, in this particular case, it might be sufficient to call waitpid()
and block the main loop. As far as I understand, KDE blocks the UI until
the MIME-thingy process exits anyhow.

Rémi Denis-Courmont

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