[Interest] Qt 5.12 official build on Ubuntu 14.04

[René J. V. Bertin]

Thiago Macieira wrote:

Hi,

1
> more likely, a *library* difference: something may be calling
> QCoreApplication::setLibraryPaths(). instead of
> QCoreApplication::addLibraryPath().

I thought about that too, but can now say that I can indeed switch between the 2 
behaviours simply by including the KDECompilerSettings ECM module or not.

This is probably determining: without that module, LD_LIBRARY_PATH has no 
effect:

%> /opt/Qt/5/5.12.1/thisQt.sh ldd qstyle-demo/build/bin/qstyle-demo | & head
        linux-vdso.so.1 =>  (0x00007ffdfe9e6000)
        libQt5Widgets.so.5 => /opt/local/libexec/qt5/lib/libQt5Widgets.so.5 
(0x00007f148a56d000)

But when I include the module ldd shows that LD_LIBRARY_PATH does have effect:
%> /opt/Qt/5/5.12.1/thisQt.sh ldd qstyle-demo/build/bin/qstyle-demo | & head
        linux-vdso.so.1 =>  (0x00007fff851a0000)
        libQt5Widgets.so.5 => /opt/Qt/5/5.12.1/gcc_64/lib/libQt5Widgets.so.5 
(0x00007f6042f34000)

This should exclude any kind of runtime software explanation.

Could --enable-new-dtags be the linker option that makes the difference? 
KDECompilerSettings also forces hidden default symbol visibility but I doubt 
that's relevant here.

> 
> Can you attach the full stderr from QT_DEBUG_PLUGINS=1 run?

%> /opt/Qt/5/5.12.1/thisQt.sh env QT_DEBUG_PLUGINS=1  qstyle-
demo/build/bin/qstyle-demo    
Found metadata in lib /opt/local/share/qt5/plugins/platforms/KWinQpaPlugin.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-org.kde.kwin.qpa"
        ]
    },
    "className": "KWinIntegrationPlugin",
    "debug": false,
    "version": 329990
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqeglfs.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "eglfs"
        ]
    },
    "className": "QEglFSIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqminimal.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqminimalegl.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimalegl"
        ]
    },
    "className": "QMinimalEglIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqoffscreen.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqvnc.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "vnc"
        ]
    },
    "className": "QVncIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqwayland-egl.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-egl"
        ]
    },
    "className": "QWaylandEglPlatformIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqwayland-
generic.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland"
        ]
    },
    "className": "QWaylandIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqwayland-
xcomposite-egl.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-xcomposite-egl"
        ]
    },
    "className": "QWaylandXCompositeEglPlatformIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqwayland-
xcomposite-glx.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "wayland-xcomposite-glx"
        ]
    },
    "className": "QWaylandXCompositeGlxPlatformIntegrationPlugin",
    "debug": false,
    "version": 329991
}


Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqxcb.so, 
metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 329991
}


QLibraryPrivate::loadPlugin failed on 
"/opt/local/share/qt5/plugins/platforms/libqxcb.so" : "Cannot load library 
/opt/local/share/qt5/plugins/platforms/libqxcb.so: 
(/opt/local/libexec/qt5/lib/libQt5Core.so.5: version `Qt_5.12' not found 
(required by /opt/Qt/5/5.12.1/gcc_64/lib/libQt5XcbQpa.so.5))"
This application failed to start because it could not find or load the Qt 
platform plugin "xcb"
in "".

Available platform plugins are: wayland-org.kde.kwin.qpa, eglfs, minimal, 
minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, 
wayland-xcomposite-glx, xcb.

Reinstalling the application may fix this problem.
Abort
Exit 134

> Can you also make
> a simple QtCore application that prints the output of
> QCoreApplication::libraryPaths() ?

Printed from that same test app, built so it launches:
%> /opt/Qt/5/5.12.1/thisQt.sh qstyle-demo/build/bin/qstyle-demo
org.kde.kwindowsystem: Loaded plugin 
"/opt/local/share/qt5/plugins/kf5/org.kde.kwindowsystem.platforms/KF5WindowSystemX11Plugin.so" 
for platform "xcb"
("/opt/Qt/5/5.12.1/gcc_64/plugins", "/usr/lib/kde4/plugins", 
"/opt/local/share/qt5/plugins", "/home/bertin/work/src/Scratch/Qt/qstyle-
demo/build/bin")

Launched using my regular Qt 5.9 install:

%> qstyle-demo/build/bin/qstyle-demo
org.kde.kwindowsystem: Loaded plugin 
"/opt/local/share/qt5/plugins/kf5/org.kde.kwindowsystem.platforms/KF5WindowSystemX11Plugin.so" 
for platform "xcb"
("/usr/lib/kde4/plugins", "/opt/local/share/qt5/plugins", 
"/home/bertin/work/src/Scratch/Qt/qstyle-demo/build/bin")