Den sön 21 juni 2020 kl 14:37 skrev Konstantin Ritt <ritt...@gmail.com>: > > > I think we then had discussions when moving from Qt 4 to Qt 5, that we will > > start requiring RTTI. > > However this was never promoted, and now you're saying people who ported > their projects with no-rtti to Qt5 had to enable rtti years ago or expect > crashes?) > > Thanks to Alberto for pointing this issue now, when the majority didn't > switch to the new LTS yet. > I, for example, didn't know the issue with dynamic_cast across dll boundaries > is not an issue anymore. > > Plz make sure the documentation is up to date and `CONFIG += rtti_off` does > nothing as of 5.15.
Don't touch CONFIG += rtti_off, since QMake can be used for non-Qt projects, who may want the ability to toggle this. Agree the docs should be updated, and it should have been more clearly communicated. The -no-rtti configure switch for Qt itself was removed with https://codereview.qt-project.org/c/qt/qtbase/+/182660 (since Qt 5.8). Elvis > > Regards, > Konstantin > > > вс, 21 июн. 2020 г. в 14:23, Lars Knoll <lars.kn...@qt.io>: >> >> >> >> > On 21 Jun 2020, at 13:10, Giuseppe D'Angelo via Development >> > <development@qt-project.org> wrote: >> > >> > Il 20/06/20 22:45, Thiago Macieira ha scritto: >> >> On Saturday, 20 June 2020 11:31:25 PDT Alberto Mardegan wrote: >> >>> I think I missed an announcement about Qt applications having to use >> >>> RTTI; on the opposite, I thought that the whole point of QMetaObject was >> >>> not to require RTTI support; has this changed? >> >> As you can see from the commit, no provision was made for no-RTTI builds. >> >> I >> >> don't think they've ben allowed since 5.0. >> > >> > The Qt coding policy document still says that no RTTI facilities are >> > allowed within Qt: >> > >> >> https://wiki.qt.io/Coding_Conventions >> > >> > (Unchanged since 2015; before, I'm sure that document was somewhere else, >> > with the same contents regarding this matter.) >> > >> > Where/when was such a change of policy decided? >> >> We didn’t want it in earlier versions of Qt for mainly two reasons. Early >> implementations had quite an overhead on library size, and dynamic_cast >> didn’t work reliable between DLL boundaries on Windows. Both problems have >> gone away many years ago. >> >> I have to go by what I remember now, but I think we then had discussions >> when moving from Qt 4 to Qt 5, that we will start requiring RTTI. The >> reasons where that dynamic_cast<> and typeid require it and it has very >> little overhead on library size (as opposed to exceptions which are still >> optional). By that time (or maybe even earlier), we also started compiling >> Qt with RTTI enabled on all platforms. >> >> But it looks like nobody ever adjusted the wiki page :/ >> >> We are making use of dynamic_cast and typeid in Qt nowadays, so I guess it’s >> high time we adjust the wiki. >> >> Cheers, >> Lars >> >> _______________________________________________ >> Development mailing list >> Development@qt-project.org >> https://lists.qt-project.org/listinfo/development > > _______________________________________________ > Development mailing list > Development@qt-project.org > https://lists.qt-project.org/listinfo/development _______________________________________________ Development mailing list Development@qt-project.org https://lists.qt-project.org/listinfo/development
