On 2018-08-03 08:03, Martin Koller wrote:
On Donnerstag, 2. August 2018 15:45:00 CEST Simon Hausmann wrote:
Hi,
Before concluding that a namespaced Qt is a terrible idea, I recommend trying
out the feature.
It is intended to work transparently and not require any changes to the
application, nothing like having to type MyNS::QString everywhere.
It may be problematic with forward declarations of Qt types, but the fix for
that (surrounding with QT_BEGIN/END_NAMESPACE) is entirely compatible between
NS and non-NS builds and does not violate the write once goal.
The correct way to use Qt classes forward declared with (and also without) a
namespaced Qt build is e.g.:
QT_FORWARD_DECLARE_CLASS(QTimer)
The problem we had with a namespaced Qt were: using external Qt based
libraries, which never tried to use
a namespaced build, did not build due to forward declarations, so I had to
patch some of them.
But then, not all external library projects liked these patches so we'd have to
patch them on our own
increasing the workload when upgrading ...
Also, when using squish you can no longer use a prebuilt version and have to
compile squish from sources
including also the namespace AFAIR.
Eventually we could go back to non-namespaced builds, which makes your life
simpler.
Ideally, we should deprecate forward declarations of Qt classes.
We should have a forwarding header, generated by syncqt, which would fordward
declare all classes on a module. So one would do #include <QtCoreFwd> to
forward declare all classes in QtCore.
--
Olivier
Woboq - Qt services and support - https://woboq.com - https://code.woboq.org
_______________________________________________
Development mailing list
[email protected]
http://lists.qt-project.org/mailman/listinfo/development
