CMake package configuration files for upstream projects using Qt5 problems -

i working on larger c++ library using cmake , depends on qt. moved qt4 qt5 , encounter problem when using our lib in upstream project. minimal working example demonstrating problem please have @ repo:

https://github.com/philthiel/cmake_qt5_upstream

it contains 2 separate cmake projects:

• mylib: tiny library uses qstring qt5::core.

  it generates , installs package configuration files mylibconfig.cmake, mylibconfigversion.cmake, , mylibtargets.cmake in order searchable cmake find_package()

• myapp: tiny executable depending on mylib

  the project uses find_package(mylib) , creates executable uses mylib

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the problem cmake gives me following error message when configuring myapp project:

cmake error @ cmakelists.txt:11 (add_executable):    target "myapp" links target "qt5::core" target not found.    perhaps find_package() call missing imported target, or    alias target missing? 

the reason behaviour in automatically generated mylibtargets.cmake file interface_link_libraries entry qt5 core qt5::core symbol. using qt4, absolute path qt core lib specified here.

---

now, can resolve using

find_package(qt5core 5.x required)  

in myapp project.

however, know if intended/generic way go, i.e. requesting upstream projects of our lib search required transitive qt5 dependencies themselves, or if misuse cmake here , need change configuration procedure?

the cmake docu on package file generation

https://cmake.org/cmake/help/v3.0/manual/cmake-packages.7.html

mentions macros can provided package configuration files upstream. maybe correct place search imported targets qt5 , break upstream configuration runs when these dependencies not found?

best, philipp

[edit of edit] full source example

you need deliver cmake config file project, , configfile should generated via cmake (because cannot know shure user install software).

tip, use ecm cmake modules ease creation of that:

 find_package(ecm required no_module)  include(cmakepackageconfighelpers)   ecm_setup_version(${project_version}     variable_prefix atcore     version_header "${cmake_current_binary_dir}/atcore_version.h"     package_version_file "${cmake_current_binary_dir}/kf5atcoreconfigversion.cmake"     soversion 1 )   configure_package_config_file("${cmake_current_source_dir}/kf5atcoreconfig.cmake.in"                                "${cmake_current_binary_dir}/kf5atcoreconfig.cmake"                           install_destination ${cmakeconfig_install_dir}   ) 

and kf5atcoreconfig.cmake.in:

@package_init@  find_dependency(qt5widgets "@required_qt_version@") find_dependency(qt5serialport "@required_qt_version@") find_dependency(kf5solid "@kf5_dep_version@")  include("${cmake_current_list_dir}/kf5atcoretargets.cmake") 

this generate correct findyoursortware.cmake dependencies.

[edit] better explanation on what's going on. if providing library use qt, , need find qt5 library before compilling user's source, need provide findyourlibrary.cmake code, call

 find_package(qt5 required components core gui widgets whatever) 

now, if it's your executable needs linked, use components instead of way doing now.

find_package(qt5 required components core) 

then link library with

 target_link_libraries(yourtarget qt5::core)