CMAKE target_include_directories 出现错误 C1083（找不到文件）

Question

我有一个 c++ 项目在源代码树中分成几个不同的库/可执行文件。有一个包含一些子目录的顶级 CMake 文件。一个叶子库 B 链接到另一个叶子库 A。但是，即使 A 已公开添加 target_include_directories，在 B 中，我也会收到错误 C1083 - 无法打开包含文件。

操作系统：Win10

使用套件 GCC 7.3.0：

• CMake 命令"C:\Program Files\CMake\bin\cmake.EXE" --no-warn-unused-cli -DMOCK_SIMCONNECT:BOOL=TRUE "-DP3D_SDK_ROOT:STRING=C:/Program Files/Lockheed Martin/Prepar3D v4 SDK 4.5.14.34698" -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_C_COMPILER:FILEPATH=C:\Qt\Tools\mingw730_64\bin\gcc.exe -DCMAKE_CXX_COMPILER:FILEPATH=C:\Qt\Tools\mingw730_64\bin\g++.exe -Hd:/repos/cmake_sample_project -Bd:/repos/cmake_sample_project/build -G "MinGW Makefiles"

• 错误信息：

[build] D:\repos\cmake_sample_project\src\B\libB.h:5:10: fatal error: libA.h: No such file or directory
[build]  #include "libA.h"
[build]           ^~~~~~~~
[build] compilation terminated.

使用工具包 Visual Studio Build Tools 2017 Release - amd64：

• CMake 命令："C:\Program Files\CMake\bin\cmake.EXE" --no-warn-unused-cli -DMOCK_SIMCONNECT:BOOL=TRUE "-DP3D_SDK_ROOT:STRING=C:/Program Files/Lockheed Martin/Prepar3D v4 SDK 4.5.14.34698" -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_BUILD_TYPE:STRING=Debug -Hd:/repos/cmake_sample_project -Bd:/repos/cmake_sample_project/build -G "Visual Studio 15 2017" -T host=x64 -A x64

• 错误信息：

d:\repos\cmake_sample_project\src\b\libB.h(5): fatal error C1083: Datei (Include) kann nicht geöffnet werden: "libA.h": No such file or directory [D:\repos\cmake_sample_project\build\src\B\libB-obj.vcxproj]

sample_cmake_project
|   CMakeLists.txt
|   
+---src
|   |   CMakeLists.txt
|   |   
|   +---A
|   |   |   CMakeLists.txt
|   |   |   libA.cpp
|   |   |   
|   |   \---public
|   |           libA.h
|   |           
|   \---B
|           CMakeLists.txt
|           libB.cpp
|           libB.h
|           
\---tests
        CMakeLists.txt

sample_cmake_project/CMakeLists.txt：

cmake_minimum_required(VERSION 3.12)

project(sample_project LANGUAGES CXX)

add_subdirectory(src)

enable_testing()
add_subdirectory(tests)

sample_cmake_project/src/CMakeLists.txt

add_subdirectory(A)
add_subdirectory(B)

sample_cmake_project/src/A/CMakeLists.txt

add_library(libA-obj OBJECT "")

target_sources(libA-obj 
    PRIVATE
        ${CMAKE_CURRENT_SOURCE_DIR}/libA.cpp
    PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}/public/libA.h # <-- header is added as public source.
)

add_library(libA STATIC $<TARGET_OBJECTS:libA-obj>)

target_include_directories(libA PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/public) # <-- public dir is added to the target's PUBLIC include directories.

include_directories(${CMAKE_CURRENT_SOURCE_DIR}/public)

sample_cmake_project/src/B/CMakeLists.txt：

add_library(libB-obj OBJECT "")

target_sources(libB-obj 
    PRIVATE
        ${CMAKE_CURRENT_SOURCE_DIR}/libB.cpp
    PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}/libB.h
)

add_library(libB STATIC $<TARGET_OBJECTS:libA-obj>)

target_link_libraries(libB PRIVATE libA)

include_directories(${CMAKE_CURRENT_SOURCE_DIR})

sample_cmake_project/src/A/public/libA.h：

#ifndef __LIBA_H
#define __LIBA_H

#include <iostream>

class A 
{
    public:
    A() { std::cout << "hello" << std::endl; };
    ~A() { std::cout << "bye bye" << std::endl; };

    void saySomething();
};

#endif

sample_cmake_project/src/A/libA.cpp：

#include "libA.h"

void A::saySomething()
{
    std::cout << "something..." << std::endl;
}

sample_cmake_project/src/B/libB.h：

#ifndef __LIB_B
#define __LIB_B

#include <iostream>
#include "libA.h"

class B
{
public:
    B();
    ~B();

    void saySomething();

private:
    A _a;
};

#endif

sample_cmake_project/src/B/libB.cpp:

#include "libB.h"

B::B() :
    _a(A())
{
    std::cout << "Hello from lib B" << std::endl;
    _a.saySomething();
}

我觉得我可能遗漏了一些基本的东西，但我认为通过将 sample_cmake_project/A/public 添加到 libA 目标的包含目录，libA.h 标头应该可用于链接到 libA 的库，例如libB?

有什么想法吗？提前致谢。

Answer 1

这是微不足道的，有点明显，但我忽略了它。错误消息涉及 libB-obj，用于制作静态库 libB 的对象库。 libB-obj 未链接到 libA，因此来自 libA 的公共包含目录不适用于 libB-obj。

add_library(libB-obj OBJECT "")

target_sources(libB-obj 
    PRIVATE
        ${CMAKE_CURRENT_SOURCE_DIR}/libB.cpp
    PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}/libB.h
)

add_library(libB STATIC $<TARGET_OBJECTS:libA-obj>)

target_link_libraries(libB-obj PRIVATE libA) # --> link libB-obj instead of static library libB!

include_directories(${CMAKE_CURRENT_SOURCE_DIR})