meet a problem when attempting to promote imported target "Threads::Threads" to global scope

novum

I ran into a problem when cross-building Qt 6.4.2 from source by following Cross-Compile_Qt_6_for_Raspberry_Pi.

the cmake produced the following output.

CMake Error at qtbase/cmake/QtPublicTargetHelpers.cmake:257 (set_property):
  Attempt to promote imported target "Threads::Threads" to global scope (by
  setting IMPORTED_GLOBAL) which is not built in this directory.
Call Stack (most recent call first):
  qtbase/cmake/QtFindPackageHelpers.cmake:180 (__qt_internal_promote_target_to_global)
  qtbase/src/corelib/CMakeLists.txt:4 (qt_find_package)

SGaist

Can you try with a more recent version of Qt ?
While I understand the motivation of staying on certain version, these kind of issue might have already been solved later.

novum

find_package(Threads) might have been called in another directory first, and that's why promoting imported target "Threads::Threads" to global scope fails here

novum

I got sysroot from latest RPi OS image.

In the sysroot, the file /usr/lib/aarch64-linux-gnu/cmake/zstd/zstdConfig.cmake has the following code,

include(CMakeFindDependencyMacro)
if(ON AND "1")
  find_dependency(Threads)
endif()

include("${CMAKE_CURRENT_LIST_DIR}/zstdTargets.cmake")

check_required_components("zstd")

novum

the host system is Ubuntu 24.04.
the RPi5 system is Debian Trixie.

SGaist

Hi,

Might be a silly question but did you properly use two separate build folders ?
Also why Qt 6.4.2 rather than a current version ?

novum

@SGaist yes, I use two separate build folders. It's in the buildhost directory to build Qt for the host machine, and in the buildrpi5 directory for the rpi5.

SGaist

You did not answer about the use of an outdated version of Qt.

novum

I migrate my application, originally developed on Ubuntu 24.04, from x86 to the RPi5.
I want to use the same Qt version to develop the application for both platforms.

I built Qt 6.4.2 from source, as the latest Raspbian ships with Qt 6.8.2.

SGaist

Can you try with a more recent version of Qt ?
While I understand the motivation of staying on certain version, these kind of issue might have already been solved later.

novum

I fixed it by checking the latest source code. : )

SGaist

Excellent !

Good luck :-)