On Monday, 11 March 2019 03:56:59 PDT René J.V. Bertin wrote: > One hurdle: my distribution uses dbus 1.6.x which lacks at least 1 function > required by libQt5Dbus. I don't really want to risk rolling my own upgrade > for that. So instead I installed dbus 1.12.12 into my usual /opt/local > parallel prefix with a suffix on the binaries and configured to use the > same runtime resources as the host dbus. That seems to work just fine, > despite the fact that it communicates through an older dbus daemon and with > other clients that will use the older libdbus library.
That shouldn't be a problem. > I do observe something very curious and surprising. All my KF5 applications > from /opt/local run just fine against this Qt 5.12 install, and a few of > the simpler "pure Qt" applications do too (like qdbusviewer and even > linguist). But most fail very quickly with this error: > > %> /opt/Qt/5/5.12.1/thisQt.sh /opt/local/libexec/qt5/bin/assistant > This application failed to start because it could not find or load the Qt > platform plugin "xcb" in "". [cut] > When I set QT_DEBUG_PLUGINS=1 I see that only plugins from the /opt/local > install are being loaded, yet I set QT_PLUGIN_PATH to list the 5.12 plugin > directory first. For good measure I added an LD_PRELOAD of the 5.12 > libQt5Core to my wrapper; makes no difference. > > The difference between these "pure Qt" and the KF5 applications is that the > former are built via qmake, the latter via cmake. Can that explain a > difference in rpath information set in the executables which makes the > LD_LIBRARY_PATH trick fail in the former? There shouldn't be anything explicitly causing this. So it must be a side effect or just a huge coincidence. If it's a side-effect, I imagine it's caused by the use of DT_RUNPATH in the ELF modules, or lack thereof. But I'm not convinced it's a build difference, you may be seeing a coincidence. Or, more likely, a *library* difference: something may be calling QCoreApplication::setLibraryPaths(). instead of QCoreApplication::addLibraryPath(). Can you attach the full stderr from QT_DEBUG_PLUGINS=1 run? Can you also make a simple QtCore application that prints the output of QCoreApplication::libraryPaths() ? -- Thiago Macieira - thiago.macieira (AT) intel.com Software Architect - Intel System Software Products _______________________________________________ Interest mailing list Interest@qt-project.org https://lists.qt-project.org/listinfo/interest
