Using Conan for Qt6

"Work in Progress"

Qt6 Additional Library src package build using Conan package manager

To build Qt6 Additional Library src packages using Conan, which is provided by the Qt Installer, you can follow these steps. Note! This is still in beta phase i.e. you may need workarounds to get it working and instructions may change later.

Building

Install required development libraries: https://doc-snapshots.qt.io/qt6-dev/gettingstarted.html#platform-requirements
Qt Installer - install:
- CMake (3.15 or higher is required)
  - the Additional Libraries use the CMake itself for the build
- Conan (installs standalone conan(.exe) executable + settings files
- Ninja (CMake generator)
- 6.0.0 essentials binary package
- Additional Library src package(s) needed in your CMake project
  - Qt Installer providesAdditional Library packages under top-level "Additional libraries" node
Put the installed tools into your PATH, prepend to PATH if needed to avoid mixing with older versions in your system
- <QtSdk>/Tools/CMake/bin
- <QtSdk>/Tools/Conan
- <QtSdk>/Tools/Ninja
Build the Additional Library conan package
- The "conan(.exe) install" commands below will install the built binaries also to your current working directory so you may want to:
  - mkdir build_dir && cd build_dir
- Windows MSVC2019:
  - For MSVC compiler open command prompt and execute vcvars64.bat
    - e.g. "C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Auxiliary\Build\vcvars64.bat
  - $conan.exe install qtnetworkauth/6.0.0@qt/beta --build=missing --profile=<QtSdk>/Tools/Conan/profiles/qt-6.0.0-msvc2019_64 -s build_type=Release -g cmake_paths -g=cmake -g deploy
- Windows MinGW81:
  - For MinGW compiler add MinGW tools location to path
  - $conan.exe install qtnetworkauth/6.0.0@qt/beta --build=missing --profile=<QtSdk>/Tools/Conan/profiles/qt-6.0.0-mingw81-x86_64 -s build_type=Release -g cmake_paths -g=cmake -g deploy
- macOS clang
  - $conan install qtnetworkauth/6.0.0@qt/beta --build=missing --profile=<QtSdk>/Tools/Conan/profiles/qt-6.0.0-macx-clang -s build_type=Release -g cmake_paths -g=cmake -g deploy
- Linux gcc
  - $conan install qtnetworkauth/6.0.0@qt/beta --build=missing --profile=<QtSdk>/Tools/Conan/profiles/qt-6.0.0-gcc-x86_64 -s build_type=Release -g cmake_paths -g=cmake -g deploy
- Currently the follwing Additional Libraries are available as Conan packages:
  - qtnetworkauth
  - qtimageformats
  - qt3d
- The cmake_paths generator will produce 'conan_paths.cmake' to your working directory, include it in your CMake project
- If you have a qmake based consuming project for theAdditional Library you can pass "-g qmake" -generator which will create 'conanbuildinfo.pri' file which you can include in your qmake project. https://docs.conan.io/en/latest/integrations/build_system /qmake.html
- After successful build the built package should exist in your Conan cache: '$HOME/.conan/data/qtnetworkauth/6.0.0/qt/beta/package' and in your current working directory
  - Note: If you have configured your Conan home/cache folder differently the built package is located there
Edit the CMakeLists.txt of your MyApp project

   include(${CMAKE_BINARY_DIR}/conan_paths.cmake)

   find_package(Qt6 COMPONENTS Widgets Network REQUIRED)
   find_package(Qt6 COMPONENTS NetworkAuth REQUIRED)

   add_executable(MyApp
     main.cpp
     mainwindow.cpp
     mainwindow.h
     mainwindow.ui
   )

   # Note! Temporary solution until fixed in Qt6 build system 
   foreach(prefix ${CMAKE_PREFIX_PATH})
       set(prefix_include "${prefix}/include")
           if(EXISTS "${prefix_include}")
               target_include_directories(MyApp PRIVATE "${prefix_include}")
           endif()
   endforeach()

   target_link_libraries(MyApp PRIVATE Qt::Widgets Qt::NetworkAuth)

Build 'MyApp'
- $ cd myapp
- $ mkdir build && cd build
- $ cmake -G Ninja -D CMAKE_INSTALL_PREFIX=<QtSdk>/6.0.0/gcc_64 -D CMAKE_BUILD_TYPE=Release ..
- $ cmake --build .
- The MyApp should be in 'bin/* directory and you should be able to launch it
Running the application
- The deploy generator "-g deploy" passed to conan deploys the build binaries from conan cache to your working directory
- Windows:
  - Put the deployed binaries to the same directory of your built application
- macOS
  - Put the deployed binaries to the same directory of your built application
  - export DYLD_FRAMEWORK_PATH with paths to 6.0.0 essentials & qtnetworkauth deploy directory
- Linux:
  - Put the deployed binaries to the same directory of your built application

Conan profiles for Qt packages

The Qt Installer installs Conan profile files for those Qt essential binary packages that are selected for installation by the user.

The profile files are installed in: <QtSdk>/Tools/Conan/profiles

The profile files contain settings that match the configuration that was used to build the matching essentials binary package.

The [env] section contains 'QT_PATH' which points to the essentials package installation. This way the add-on Conan build recipe can locate the qt.toolchain.cmake file which is needed by the build recipe to build the Additional Library.

For Boot to Qt targets (Boot2Qt), the profiles do not have the QT_PATH env set and user needs to give this as environment variable when using conan (-e , --env) to point to the selected toolchain.

The profiles can be found from: https://code.qt.io/cgit/qt/qt-conan-config.git/ (https://codereview.qt-project.org/admin/repos/qt/qt-conan-config)

In case you want to install profiles by your self e.g. to some other location or you did not use Qt installer to install those you can use the following command:

- $conan config install <git-repo> -sf <path-in-git-repo> -tf <destination-path>

- e.g. $conan config install git://code.qt.io/qt/qt-conan-config.git -sf profiles/qt/linux/6.0.0 -tf /home/<user>/temp_path

Further notes

Ninja is the recommended CMake generator and should be used. E.g. on Windows you may get compilation time errors if using VS generator