首次使用CMake搭建项目遇编译问题，寻求配置协助

Hey there! No worries at all—everyone fumbles a bit when first getting their hands on CMake, especially when mixing in git submodules. Let's break this down step by step to get your project compiling.

First, Let's Grab Some Key Details #

To pinpoint the exact issue quickly, could you share:

• The full error messages you're seeing when trying to compile (copy-paste the entire output if you can—even the "minor" warnings might help)
• The exact content of all three CMakeLists.txt files
• A clear breakdown of your directory structure (e.g., where main.cc lives relative to these files, what source files are in libfoo)

Example Working Configurations #

While we wait for those details, here's a typical solid setup for your project structure that you can compare against your current files:

Root Directory CMakeLists.txt #

This file sets up the project, ensures your submodule is ready, and includes the necessary subdirectories:

cmake_minimum_required(VERSION 3.10)
project(MyProject)

# Make sure the git submodule is initialized (in case it wasn't pulled properly)
find_package(Git QUIET)
if(GIT_FOUND AND EXISTS "${PROJECT_SOURCE_DIR}/.git")
    option(GIT_SUBMODULE "Check submodules during build" ON)
    if(GIT_SUBMODULE)
        message(STATUS "Updating git submodules...")
        execute_process(COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive
                        WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
                        RESULT_VARIABLE SUBMOD_RESULT)
        if(NOT SUBMOD_RESULT EQUAL "0")
            message(FATAL_ERROR "Failed to update submodules! Try running `git submodule update --init --recursive` manually first.")
        endif()
    endif()
endif()

# Add the libfoo submodule first so its targets are available to the main app
add_subdirectory(libfoo)
# Add your main application directory
add_subdirectory(main)

libfoo/CMakeLists.txt #

This defines the library target that your main executable will link against:

# Create a static library target (use SHARED instead if you need a dynamic library)
add_library(libfoo STATIC
    # List all source files for libfoo here, e.g.:
    foo.cpp
    foo.h
)

# Make libfoo's include directory accessible to other targets that link against it
target_include_directories(libfoo PUBLIC
    ${CMAKE_CURRENT_SOURCE_DIR}
)

main/CMakeLists.txt #

This builds your main executable and links it to the libfoo library:

# Create the main application executable
add_executable(my_app main.cc)

# Link the executable against the libfoo target from the submodule
target_link_libraries(my_app PRIVATE libfoo)

Common Pitfalls to Check Right Now #

• Uninitialized submodule: Run git submodule update --init --recursive in your project root to make sure all of libfoo's files are actually present on your machine.
• Mismatched target names: If libfoo's CMakeLists defines a target named foo instead of libfoo, your main CMakeLists needs to link against foo instead.
• Missing include directories: If main.cc can't find libfoo's headers, double-check that target_include_directories in libfoo's CMakeLists uses PUBLIC (not PRIVATE) so the path gets passed to linked targets.
• Outdated CMake version: Make sure the minimum version in your root CMakeLists is compatible with whatever libfoo requires.

Once you share your error logs and current config files, we can zero in on the exact problem!

内容的提问来源于stack exchange，提问作者del