Qt-6.2.0: You need to set QT_HOST_PATH to cross compile Qt.

[debian]

Hello!
According to https://www.qt.io/blog/qt-6-build-system I can use QT_BUILD_TOOLS_WHEN_CROSS_COMPILING for build host tools during cross-compile, I try this and unfortunately this is not work

./configure .... \
    -- \
    -DCMAKE_TOOLCHAIN_FILE=$(BUILD_DIR)/toolchain.cmake \
    -DQT_BUILD_TOOLS_WHEN_CROSSCOMPILING=ON

Follow console output

-- Detecting C compiler ABI info - done
-- Check for working C compiler: /tmp/firmware/toolchain/gcc-linaro-11.0.1-2021.03-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
CMake Error at cmake/QtSetup.cmake:196 (message):
  You need to set QT_HOST_PATH to cross compile Qt.
Call Stack (most recent call first):
  cmake/QtBuildInternals/QtBuildInternalsConfig.cmake:229 (include)
  cmake/QtBuildInternals/QtBuildInternalsConfig.cmake:372 (qt_build_internals_set_up_private_api)
  CMakeLists.txt:91 (qt_build_repo_begin)


-- Configuring incomplete, errors occurred!

Why and how can I fix this?
Thank you.

[jsulm]

@debian said in Qt-6.2.0: You need to set QT_HOST_PATH to cross compile Qt.:

Why and how can I fix this?

You need to do what the error message suggests.
See https://doc.qt.io/qt-6/cmake-variable-qt-host-path.html

[debian]

@jsulm , you mean what https://www.qt.io/blog/qt-6-build-system incorrect and QT_BUILD_TOOLS_WHEN_CROSS_COMPILING is not work? QT_BUILD_TOOLS_WHEN_CROSS_COMPILING is a useless if I have prebuilded host-Qt, this is mean what I should buld of Qt two time.

[jsulm]

@debian said in Qt-6.2.0: You need to set QT_HOST_PATH to cross compile Qt.:

you mean

No, that's not what I mean. I think you need to set QT_HOST_PATH in addition to QT_BUILD_TOOLS_WHEN_CROSS_COMPILING.

[debian]

I was try use -qt-host-path, but this is now work at this is case

...............
CMake Error at cmake/QtSetup.cmake:201 (find_package):
  Could not find a package configuration file provided by "Qt6HostInfo" with
  any of the following names:

    Qt6HostInfoConfig.cmake
    qt6hostinfo-config.cmake

  Add the installation prefix of "Qt6HostInfo" to CMAKE_PREFIX_PATH or set
  "Qt6HostInfo_DIR" to a directory containing one of the above files.  If
  "Qt6HostInfo" provides a separate development package or SDK, be sure it
  has been installed.
Call Stack (most recent call first):
  cmake/QtBuildInternals/QtBuildInternalsConfig.cmake:229 (include)
  cmake/QtBuildInternals/QtBuildInternalsConfig.cmake:372 (qt_build_internals_set_up_private_api)
  CMakeLists.txt:91 (qt_build_repo_begin)


-- Configuring incomplete, errors occurred!

configure check this is directory to several files, so this is variable is a directory with early installed Qt, not path fo install host tools.

[debian]

Look like what this is now work
cmake/QtSetup.cmake

.................
## Find host tools (if non native):
set(QT_HOST_PATH "" CACHE PATH "Installed Qt host directory path, used for cross compiling.")

if (CMAKE_CROSSCOMPILING)
    if(NOT IS_DIRECTORY "${QT_HOST_PATH}")
        message(FATAL_ERROR "You need to set QT_HOST_PATH to cross compile Qt.")
    endif()
endif()

if(NOT "${QT_HOST_PATH}" STREQUAL "")
    find_package(${INSTALL_CMAKE_NAMESPACE}HostInfo
                 CONFIG
                 REQUIRED
                 PATHS "${QT_HOST_PATH}"
                       "${QT_HOST_PATH_CMAKE_DIR}"
                 NO_CMAKE_FIND_ROOT_PATH
                 NO_DEFAULT_PATH)
endif()

So configure always check host-files, this bug or I'm incorrect understand https://www.qt.io/blog/qt-6-build-system ?

The cross-built Qt does not build the host tools for the target platform, unless you set the CMake variable QT_BUILD_TOOLS_WHEN_CROSS_COMPILING to ON. Doing so is useful in embedded Linux environments

[debian]

https://doc-snapshots.qt.io/qt6-6.2/configure-linux-device.html describe same parameters

[ad1170]

Just if anyone interested in. I have used the configure option -qt-host-path /home/[user]/Qt/6.2.2/gcc_64 when building e.g. qt for android on ubuntu.