Dependencies across multiproject in CMake

artwaw

Good afternoon,
can someone clarify please:

I have a project composed (for now) of a library and desktop project
library uses network and sql, while desktop does not
I can't compile target desktop because it complains about network classes, which are not a part of this project at all (library itself is).

Root cmakelists:

cmake_minimum_required(VERSION 3.5)

project(
  boilerplate
  LANGUAGES CXX
  VERSION 0.1
  DESCRIPTION "boilerplate client")


set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Qt6 REQUIRED COMPONENTS Core Widgets Gui LinguistTools)
#above is used in both lib and the program
qt_standard_project_setup()
add_subdirectory(Core)
add_subdirectory(Desktop)

Library cmakelists:

find_package(Qt6 REQUIRED COMPONENTS Network Sql)

set(TS_FILES Core_en_GB.ts)

qt_add_library(Core SHARED
  core.h   core.cpp
  ${TS_FILES}
  logger.h logger.cpp
  ipmodel.h ipmodel.cpp
  core.qrc
  cookiejar.h cookiejar.cpp
)
target_link_libraries(Core PRIVATE Qt6::Core)
target_link_libraries(Core PRIVATE Qt6::Network)
target_link_libraries(Core PRIVATE Qt6::Sql)
target_link_libraries(Core PRIVATE Qt6::Gui)
target_include_directories(Core INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
target_compile_definitions(Core PRIVATE BLACORE_LIBRARY)
qt_create_translation(QM_FILES ${CMAKE_SOURCE_DIR} ${TS_FILES})

Desktop cmakelists:

set(TS_FILES Desktop_en_GB.ts)
set(PROJECT_SOURCES
        main.cpp
        blab.h blab.cpp blab.ui
        ${TS_FILES}
)
qt_add_executable(Desktop
        MANUAL_FINALIZATION
        ${PROJECT_SOURCES}
        desktop.rc desktop.qrc
)
qt_create_translation(QM_FILES ${CMAKE_SOURCE_DIR} ${TS_FILES})
target_link_libraries(Desktop PRIVATE Qt6::Core)
target_link_libraries(Desktop PRIVATE Qt6::Widgets)
target_link_libraries(Desktop PRIVATE Qt6::Gui)
target_link_libraries(Desktop PRIVATE Core)
set_target_properties(Desktop PROPERTIES
    ${BUNDLE_ID_OPTION}
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
    OUTPUT_NAME "Desktop boilerplate"
    MACOSX_BUNDLE TRUE
    WIN32_EXECUTABLE TRUE
)
include(GNUInstallDirs)
install(TARGETS Desktop
    BUNDLE DESTINATION .
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)
qt_finalize_executable(Desktop)

The exact error I get while compiling from the root level is:

In file included from "[..]/lib/core.h:6"
from "[..]/Desktop/blab.h:5"
from "[..]/Desktop/main.cpp:1"
[..]/lib/cookiejar.h:4:10": fatal error: QNetworkCookieJar: No such file or directory

I can build the library itself just fine. I don't recall having such issues in the past.

Christian Ehrlicher

You have to link PUBLIC to the libraries which you're using in your headers (which should be used by others). Please see the CMake documentation.

JoeCFD

@artwaw did you add include path of your lib?

artwaw

@JoeCFD In this project I followed what seems to be updated documentation from Qt, where they say the line in the lib's cmakelists target_include_directories(Core INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}) is sufficient (certainly seems that way, core.h is found in Desktop target).

source https://doc.qt.io/qt-6/cmake-get-started.html

By calling target_include_directories, we make sure that the absolute path to the [library] directory is automatically added as an include path to all targets using our library.

Should I scrap this and do the usual, pure cmake way?

JoeCFD

@artwaw It looks like you may need include path of network module as well.

Christian Ehrlicher

You have to link PUBLIC to the libraries which you're using in your headers (which should be used by others). Please see the CMake documentation.

artwaw

@Christian-Ehrlicher My bad. Thank you, it worked! I need to up my cmake game...