Qt-version related runtime errors in Qt application

Question

I am using Qt Creator to develop and run an application on Linux KDE neon.

My application suddenly refuses to open some URLs, a function that properly worked before. I didn't change anything so I guess some KDE neon updates broke it.

When calling that function I get this debug output:

kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5KIOWidgets.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5KIOCore.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5I18n.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5CoreAddons.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5JobWidgets.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5Service.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5Completion.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5IconThemes.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5WindowSystem.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5ConfigWidgets.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5ConfigGui.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5ConfigCore.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5DBusAddons.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5Auth.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5Archive.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5ItemViews.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5Codecs.so.5)
kde-open5: /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5: version `Qt_5.11' not found (required by /usr/lib/x86_64-linux-gnu/libKF5GuiAddons.so.5)

AFAIK the two paths mentioned above are concurrent to each other because one is created by the distribution and one by Qt Creator.

The solution should be using -rpath when linking the application. My application is built with the following command line:

gcc -Wl,-rpath,/home/<user>/Qt/5.10.0/gcc_64/lib .....

Looks fine to me. Also the following is passed to gcc:

-L/home/<user>/Qt/5.10.0/gcc_64/lib

What is missing here? Why does my application depend from Qt 5.11 libraries while the build process sets the correct Qt 5.10 path?

UPDATE, this is what ldd says about my executable.

linux-vdso.so.1 =>  (0x00007ffd08b1e000)
libQt5Widgets.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Widgets.so.5 (0x00007faa1849b000)
libQt5Gui.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Gui.so.5 (0x00007faa17cb3000)
libQt5DBus.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5DBus.so.5 (0x00007faa17a23000)
libQt5Xml.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Xml.so.5 (0x00007faa177e3000)
libQt5Script.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Script.so.5 (0x00007faa1735b000)
libQt5XmlPatterns.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5XmlPatterns.so.5 (0x00007faa16d83000)
libQt5Network.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Network.so.5 (0x00007faa169eb000)
libQt5Core.so.5 => /home/<user>/Qt/5.10.0/gcc_64/lib/libQt5Core.so.5 (0x00007faa1629b000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007faa1607b000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007faa15cf3000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007faa159e3000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007faa157cb000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007faa153fb000)
/lib64/ld-linux-x86-64.so.2 (0x00007faa18cdb000)
libGL.so.1 => /usr/lib/x86_64-linux-gnu/mesa/libGL.so.1 (0x00007faa15183000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007faa14f63000)
libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007faa14d13000)
libicui18n.so.56 => /home/<user>/Qt/5.10.0/gcc_64/lib/libicui18n.so.56 (0x00007faa14873000)
libicuuc.so.56 => /home/<user>/Qt/5.10.0/gcc_64/lib/libicuuc.so.56 (0x00007faa144bb000)
libicudata.so.56 => /home/<user>/Qt/5.10.0/gcc_64/lib/libicudata.so.56 (0x00007faa12ad3000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007faa128cb000)
libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007faa126c3000)
libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007faa123ab000)
libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007faa1217b000)
libxcb-dri3.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri3.so.0 (0x00007faa11f73000)
libxcb-present.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-present.so.0 (0x00007faa11d6b000)
libxcb-sync.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007faa11b63000)
libxshmfence.so.1 => /usr/lib/x86_64-linux-gnu/libxshmfence.so.1 (0x00007faa1195b000)
libglapi.so.0 => /usr/lib/x86_64-linux-gnu/libglapi.so.0 (0x00007faa1172b000)
libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007faa11513000)
libXdamage.so.1 => /usr/lib/x86_64-linux-gnu/libXdamage.so.1 (0x00007faa1130b000)
libXfixes.so.3 => /usr/lib/x86_64-linux-gnu/libXfixes.so.3 (0x00007faa11103000)
libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007faa10efb000)
libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007faa10bbb000)
libxcb-glx.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-glx.so.0 (0x00007faa1099b000)
libxcb-dri2.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri2.so.0 (0x00007faa10793000)
libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007faa1056b000)
libXxf86vm.so.1 => /usr/lib/x86_64-linux-gnu/libXxf86vm.so.1 (0x00007faa10363000)
libdrm.so.2 => /usr/lib/x86_64-linux-gnu/libdrm.so.2 (0x00007faa1014b000)
libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007faa18e43000)
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007faa0fedb000)
libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007faa0fcd3000)
libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007faa0facb000)
libselinux.so.1 => /lib/x86_64-linux-gnu/libselinux.so.1 (0x00007faa0f8a3000)
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007faa0f69b000)
liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007faa0f473000)
libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007faa0f18b000)
libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007faa0ef73000)

UPDATE2, /sbin/ldconfig -v 2>/dev/null | grep -v ^$'\t' results in:

/usr/lib/x86_64-linux-gnu/libfakeroot:
/lib/i386-linux-gnu:
/usr/lib/i386-linux-gnu:
/usr/lib/i386-linux-gnu/mesa:
/usr/local/lib:
/lib/x86_64-linux-gnu:
/usr/lib/x86_64-linux-gnu:
/usr/lib/x86_64-linux-gnu/mesa-egl:
/usr/lib/x86_64-linux-gnu/mesa:
/lib:
/usr/lib:
/usr/lib/i386-linux-gnu/sse2: (hwcap: 0x0000000004000000)

echo $LD_LIBRARY_PATH prints nothing.

Answer 1

-rpath hardcodes the run-time library search path in an executable file or library. It does not affect linker search paths, so your application is linked with the system Qt libraries. You should pass the same path through -L option:

gcc -Wl,-rpath,/home/<user>/Qt/5.10.0/gcc_64/lib -L/home/<user>/Qt/5.10.0/gcc_64/lib ...

Here is more info:

Why is -L needed when -rpath is used?

What's the difference between -rpath and -L?