Cross compiling QtSerialBus for raspberry pi 3 complains that QtSerialPort is not available

Siron777

Hi,

I am cross compiling qt 5.10 for my raspberry pi 3. Everything want more or less well (with a lot of perseverance), but I have a last issue with the last module I would like to build: QtSerialBus. At the compilation, there is the following error:
"Some of the required modules (qtHaveModule(serialport)) are not available."
"Skipped."

I have built Qt with the following command:

configure.bat -release -platform win32-g++ -xplatform linux-arm-gnueabihf-g++ -release -opensource -confirm-license -sysroot C:/dev/tools/SysGCC/raspberry/arm-linux-gnueabihf/sysroot -prefix /usr/local/qt5 -device-option CROSS_COMPILE=C:/dev/tools/SysGCC/raspberry/bin/arm-linux-gnueabihf- -no-gui -no-widgets -no-opengl -nomake tests -nomake examples -no-use-gold-linker

make install

Then, I have build the QtSerialModule and QtRemoteObjects module following those steps:

make a subdirectory in the build folder with the name of the module and go within
Call qmake.exe /path/to/Qt_sources/qtXXX
Run make install

Everything went well for those two modules. I tried to do the same for QtSerialBus, without success.
What did I miss ? How can I make the link with the previous build of the module QtSerialPort ?

Thank you in advance for your help.

Simon

SGaist

Hi and welcome to devnet,

Are you sure you are invoking the correct version of qmake.exe ?

Siron777

Yes. I retried by calling explicitly qmake.exe from my cross compilation build for qtserialport and qtserialbus, and it produces the same result.

How does the build process determine that I have or not the required module ? Is it looking into the path ? Is it looking into leftover build artifact of qtserialport ?

SGaist

When you build a Qt module, the dependencies are listed in the QT += lines. This will trigger an inclusion of the corresponding pri files that you can find in the mkspecs/modules.

Siron777

Thank you SGaist.

I look at the big output of the qmake -d. It seems to browse a few directories to find the pri files of the modules, but never the good ones. After further investigation, I found that the function from qt_config.prf looks also in the QMAKEMODULES environment variable to configure the list of folders where to find the modules. After configuring this variable to my *.pri folder in qt installation path of the sysroot folder, the module qtserialport was found !

I think I will create a bug on the qt bug tracker. I really do not see what I miss to have that bug in my configuration of the qt build.