Build on Linux: -qt-xcb option?

[SeanMurphy_6]

I had this exact same problem and I found that if I combined the installing the packages listed by Joshua Fletcher on 16 Jun 2020:

• libxcb-devel
• libxkbcommon-devel
• xcb-util-devel
• xcb-util-image-devel
• xcb-util-keysyms-devel
• xcb-util-renderutil-devel
• xcb-util-wm-devel
• mesa-libGL-devel

And then running configure with the options suggested by Ludek Vodicka on 19 Jun 2020:

• -xcb
• -xcb-xlib
• -bundled-xcb-xinput

Built Qt and correctly built the libqxcb.so under the platforms plugin directory, and now my applications compiled against Qt 5.15.2 launch without any errors.

[nikhil-sethi]

Hey everyone. I was facing the same issue on Ubuntu 20.04. This thread and @SeanMurphy_6's solution (23rd Nov) helped me a lot. Thanks for that.
Just wanted to add that it is important to use the 'dev' versions of the xcb libraries. In my case I had the latest 'xcb xinerama0' library installed but libqxcb.so still didn't compile. Fixed it by installing the dev version (libxcb-xinerama0-dev on Debian/Ubuntu). If all xcb libraries are installed correctly, you should

1. See a 'yes' for each xcb library on the CLI when running the configure command:

Checking XCB XINERAMA .... yes 

2. See a 'succeeded' for tests in the config.log file:

test config.qtbase_gui.libraries.xcb_xinerama succeeded

When compiled you should see libqxcb.so in the qtbase/plugins/platforms directory
The original software ran perfectly after ensuring this.

[jrb1]

In case this might help someone, there appears to be a bug in configure with respect to the iccc such that with Qt-5.12.6 on RHEL7, despite having it installed the config log says:

loaded result for library config.qtbase_gui.libraries.xcb_icccm
Trying source 0 (type pkgConfig) of library xcb_icccm ...
+ /bin/pkg-config --exists --silence-errors xcb-icccm '>=' 0.3.9
pkg-config did not find package.
  => source produced no result.
Trying source 1 (type inline) of library xcb_icccm ...
xcb/xcb_icccm.h not found in [] and global paths.
  => source produced no result.
test config.qtbase_gui.libraries.xcb_icccm FAILED

I'm very sure I have that package installed (RHEL7's latest which is 0.27.1) which should have passed that version check, if I run that command myself I see it should have found it:

bash-4.2$ /bin/pkg-config --exists --silence-errors xcb-icccm '>=' 0.3.9
bash-4.2$ echo $?
0

Now pick a version I know I don't have to check pkg-config is working:

bash-4.2$ /bin/pkg-config --exists --silence-errors xcb-icccm '>=' 0.28.9
bash-4.2$ echo $?
1
bash-4.2$ /bin/pkg-config --version xcb-icccm
0.27.1
bash-4.2$ /bin/pkg-config --libs xcb-icccm
-lxcb-icccm -lxcb 

echoing $? gives you the result of the last command, 0 is "success" on unix-like OSes, non-zero is fail. Something odd is happening in that test.

If you were looking to install this library on RHEL7 the package name you need is xcb-util-wm-devel. Unfortunately that doesn't help in this case.

[mschilling]

@jrb1 Using the latest version of RHEL7, I had this issue and found that I had to install xcb-util-wm-devel before installing other xcb* libraries. I tested this by removing xcb-util-wm-devel and xcb-util-wm then re-installing just xcb-util-wm-devel and re-configuring. There seems to be a bug in RHEL7 with the way this it is packaged.

Thank you for your post, you helped me fix my issue, along with @SeanMurphy_6 and @ludek-vodicka posts.

[JonathonM]

This thread helped me immensely. I found on my CentOS 7 system, I also had to install libxkbcommon-x11-devel.
Hope this helps someone.