Ubuntu环境下基于Qt Creator v6.0.1，将MyLib配置为共享库并在MyApp中调用的CMakeLists.txt修改方案咨询

Hey there! Let's walk through the exact changes you need to make to both CMakeLists.txt files to turn MyLib into a shared library and get MyApp calling it properly.

1. Modify MyLib's CMakeLists.txt (path: MyApp/libs/MyLib/CMakeLists.txt) #

Replace or update the content with the following, adjusting source filenames to match your actual code:

# Minimum CMake version (v3.16+ works well with Qt 6)
cmake_minimum_required(VERSION 3.16)

# Project name and version
project(MyLib VERSION 1.0.0 LANGUAGES CXX)

# Set C++ standard to match Qt's requirements
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# Add Qt modules if MyLib uses Qt (remove these lines if it's a plain C++ library)
find_package(Qt6 REQUIRED COMPONENTS Core)
qt_standard_project_setup()

# Build MyLib as a shared library (.so file on Linux)
add_library(MyLib SHARED
    src/mylib.cpp  # Replace with your actual source files from MyLib/src
    # Add other .cpp files here if needed
)

# Link Qt modules to MyLib (remove if not using Qt)
target_link_libraries(MyLib PRIVATE Qt6::Core)

# Expose MyLib's include directory to dependent projects
target_include_directories(MyLib PUBLIC
    ${CMAKE_CURRENT_SOURCE_DIR}/include
)

# Optional: Set shared library version properties
set_target_properties(MyLib PROPERTIES
    VERSION ${PROJECT_VERSION}
    SOVERSION 1
)

Key changes explained: #

• add_library(MyLib SHARED): Tells CMake explicitly to build MyLib as a shared library instead of the default static library.
• target_include_directories(MyLib PUBLIC ...): Marks MyLib's include folder as public, so any project linking to MyLib automatically gets access to its header files.
• Qt-related lines: Keep these only if MyLib uses Qt modules (like Core, Widgets). If it's a plain C++ library, you can safely remove those lines.

2. Modify MyApp's Root CMakeLists.txt (path: MyApp/CMakeLists.txt) #

Update the file to include and link MyLib, adjusting for your app's actual source files:

cmake_minimum_required(VERSION 3.16)

project(MyApp VERSION 1.0.0 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# Find Qt modules your app needs (adjust based on your app's functionality)
find_package(Qt6 REQUIRED COMPONENTS Core Widgets)
qt_standard_project_setup()

# Add MyLib as a subdirectory - this builds MyLib before MyApp
add_subdirectory(libs/MyLib)

# Create MyApp executable
add_executable(MyApp
    src/main.cpp
    src/mainwindow.cpp  # Replace with your app's source files from MyApp/src
    # Add other .cpp files here if needed
)

# Link MyApp to MyLib and Qt modules
target_link_libraries(MyApp PRIVATE
    MyLib  # Link against the shared MyLib we built
    Qt6::Core
    Qt6::Widgets
)

# Optional: Keep executable output in your existing build directory structure
set_target_properties(MyApp PROPERTIES
    RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/build/$<CONFIG>
)

Key changes explained: #

• add_subdirectory(libs/MyLib): Instructs CMake to process MyLib's build first, ensuring the shared library is ready when linking MyApp.
• target_link_libraries(MyApp PRIVATE MyLib): Connects MyApp to the MyLib shared library, so your app can call functions/classes from MyLib.
• The RUNTIME_OUTPUT_DIRECTORY setting ensures your app's executable lands in the build/Debug or build/Release folders you already set up.

Final Quick Checks #

• Make sure all MyLib header files are placed in MyApp/libs/MyLib/include (e.g., include/mylib.h).
• When you build MyApp in Qt Creator, CMake will first compile MyLib into libMyLib.so (in MyApp/libs/MyLib/build/<CONFIG>), then link it to MyApp automatically.

内容的提问来源于stack exchange，提问作者VRoman