如何正确链接库与cmake？ [英] How to properly link libraries with cmake?

问题描述

我已经查看过，并尝试了一些东西与我的 CmakeLists.txt ，但我做错了，因为我不能得到我正在使用的其他库正确链接到我的项目。

I've looked all over, and tried a ton of things with my CmakeLists.txt, but I'm doing something wrong, because I can't get the additional libraries I am working with to link into my project properly.

我使用CLion，它使用cmake来构建它的项目。我试图使用几个库结合OpenGL来纹理一些对象。我最初在Visual Studio中构建它，因为我不知道如何获得cmake与Clion合作。但是，现在代码都是工作的（无论如何在Visual Studio中），我想能够使用CLion，因为那是我首选的IDE。

I am using CLion, which uses cmake to build it's projects. I am trying to use several libraries in conjunction with OpenGL to texture some objects. I initially built it in Visual Studio, because I couldn't ever figure out how to get cmake to work with Clion. However, now that the code is all working (in Visual Studio, anyways), I want to be able to use CLion for it, because that is my preferred IDE.

我还是新的cmake，我不明白我做错了我的 CMakeLists.txt 。这是我有的：

I am still new to cmake, and I don't understand what I am doing wrong with my CMakeLists.txt. Here is what I have:

cmake_minimum_required(VERSION 3.3)
project(texture_mapping)
find_package(OpenGL REQUIRED)
link_directories(${OPENGL_gl_LIBRARY})

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

set(SOURCE_FILES main.cpp camera.h display.h display.cpp mesh.cpp mesh.h obj_loader.cpp obj_loader.h shader.cpp shader.h stb_image.c stb_image.h texture.cpp texture.h transform.h)

link_directories(texture_mapping ${PROJECT_SOURCE_DIR}/lib)

add_executable(texture_mapping ${SOURCE_FILES})

target_include_directories(texture_mapping PUBLIC ${PROJECT_SOURCE_DIR}/include)
target_link_libraries(texture_mapping SDL2 SDL2main SDL2test glew32 glew32s ${OPENGL_gl_LIBRARY})

我将其调整为在我的代码中仍然无法识别头文件。

I tweaked it until it didn't give me any more errors in CLion, but the header files are still not recognized in my code.

这里是我的项目的结构：

Here is the structure of my project:

所以，我把所有的图书馆我需要，但它似乎没有在码。 Clion在项目中识别他们（他们不会出现红色错误），但当它建立（当我试图运行它在CLION），我得到这些错误：

So, I put all of the libraries I needed, but it doesn't appear to be recognizing them in the code. Clion recognizes them in the project (they aren't appearing red with errors), but when it is built (when I attempt to run it in CLion), I get these errors:

CMakeFiles\texture_mapping.dir/objects.a(mesh.cpp.obj): In function `ZN4MeshD2Ev':
...texture-mapping/mesh.cpp:30: undefined reference to `_imp____glewDeleteVertexArrays'
CMakeFiles\texture_mapping.dir/objects.a(mesh.cpp.obj): In function `ZN4Mesh8InitMeshERK12IndexedModel':
...texture-mapping/mesh.cpp:36: undefined reference to `_imp____glewGenVertexArrays'
...texture-mapping/mesh.cpp:37: undefined reference to `_imp____glewBindVertexArray'
...texture-mapping/mesh.cpp:39: undefined reference to `_imp____glewGenBuffers'
...texture-mapping/mesh.cpp:40: undefined reference to `_imp____glewBindBuffer'
...texture-mapping/mesh.cpp:41: undefined reference to `_imp____glewBufferData'
...texture-mapping/mesh.cpp:43: undefined reference to `_imp____glewEnableVertexAttribArray'
...texture-mapping/mesh.cpp:44: undefined reference to `_imp____glewVertexAttribPointer'
...texture-mapping/mesh.cpp:46: undefined reference to `_imp____glewBindBuffer'
...texture-mapping/mesh.cpp:47: undefined reference to `_imp____glewBufferData'
...texture-mapping/mesh.cpp:49: undefined reference to `_imp____glewEnableVertexAttribArray'
...texture-mapping/mesh.cpp:50: undefined reference to `_imp____glewVertexAttribPointer'
...texture-mapping/mesh.cpp:52: undefined reference to `_imp____glewBindBuffer'
...texture-mapping/mesh.cpp:53: undefined reference to `_imp____glewBufferData'
...texture-mapping/mesh.cpp:55: undefined reference to `_imp____glewBindVertexArray'
...texture-mapping/mesh.cpp:56: undefined reference to `_imp____glewBindVertexArray'
CMakeFiles\texture_mapping.dir/objects.a(mesh.cpp.obj): In function `ZN4Mesh4DrawEv':
...texture-mapping/mesh.cpp:61: undefined reference to `_imp____glewBindVertexArray'
...texture-mapping/mesh.cpp:65: undefined reference to `_imp____glewBindVertexArray'
CMakeFiles\texture_mapping.dir/objects.a(shader.cpp.obj): In function `ZN6ShaderC2ERKSs':
...texture-mapping/shader.cpp:5: undefined reference to `_imp____glewCreateProgram'
...texture-mapping/shader.cpp:11: undefined reference to `_imp____glewAttachShader'
...texture-mapping/shader.cpp:14: undefined reference to `_imp____glewBindAttribLocation'
...texture-mapping/shader.cpp:15: undefined reference to `_imp____glewBindAttribLocation'
...texture-mapping/shader.cpp:17: undefined reference to `_imp____glewLinkProgram'
...texture-mapping/shader.cpp:20: undefined reference to `_imp____glewValidateProgram'
...texture-mapping/shader.cpp:23: undefined reference to `_imp____glewGetUniformLocation'
CMakeFiles\texture_mapping.dir/objects.a(shader.cpp.obj): In function `ZN6Shader4BindEv':
...texture-mapping/shader.cpp:28: undefined reference to `_imp____glewUseProgram'
CMakeFiles\texture_mapping.dir/objects.a(shader.cpp.obj): In function `ZN6Shader6UpdateERK9TransformRK6Camera':
...texture-mapping/shader.cpp:35: undefined reference to `_imp____glewUniformMatrix4fv'
CMakeFiles\texture_mapping.dir/objects.a(shader.cpp.obj): In function `ZN6ShaderD2Ev':
...texture-mapping/shader.cpp:42: undefined reference to `_imp____glewDetachShader'
...texture-mapping/shader.cpp:43: undefined reference to `_imp____glewDeleteShader'
...texture-mapping/shader.cpp:46: undefined reference to `_imp____glewDeleteProgram'
CMakeFiles\texture_mapping.dir/objects.a(shader.cpp.obj): In function `ZN6Shader16CheckShaderErrorEjjbRKSs':
...texture-mapping/shader.cpp:79: undefined reference to `_imp____glewGetProgramiv'
...texture-mapping/shader.cpp:81: undefined reference to `_imp____glewGetShaderiv'
...texture-mapping/shader.cpp:86: undefined reference to `_imp____glewGetProgramInfoLog'
...texture-mapping/shader.cpp:88: undefined reference to `_imp____glewGetShaderInfoLog'
CMakeFiles\texture_mapping.dir/objects.a(shader.cpp.obj): In function `ZN6Shader12CreateShaderERKSsj':
...texture-mapping/shader.cpp:96: undefined reference to `_imp____glewCreateShader'
...texture-mapping/shader.cpp:109: undefined reference to `_imp____glewShaderSource'
...texture-mapping/shader.cpp:110: undefined reference to `_imp____glewCompileShader'
CMakeFiles\texture_mapping.dir/objects.a(texture.cpp.obj): In function `ZN7Texture4BindEj':
...texture-mapping/texture.cpp:36: undefined reference to `_imp____glewActiveTexture'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x24): undefined reference to `SDL_SetMainReady'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x55): undefined reference to `SDL_malloc'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x84): undefined reference to `SDL_wcslen'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0xa5): undefined reference to `SDL_iconv_string'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0xcf): undefined reference to `SDL_free'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0xf4): undefined reference to `SDL_wcslen'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x10f): undefined reference to `SDL_iconv_string'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x143): undefined reference to `SDL_malloc'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x17f): undefined reference to `SDL_free'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x18b): undefined reference to `SDL_free'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x1d6): undefined reference to `SDL_isspace'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x295): undefined reference to `SDL_isspace'
...texture-mapping/lib/SDL2main.lib(./Win32/Release/SDL_windows_main.obj):(.text+0x3a2): undefined reference to `SDL_ShowSimpleMessageBox'

基本上，每次使用SDL和glew时出错，但不是glm，这很奇怪。

Basically, errors with every usage of SDL and glew, but not glm, which is strange.

我的 CMakeLists.txt 有什么问题？

推荐答案

我的建议是开始简单，然后使您的项目进一步复杂化。

My recommendation is to start simple, and then complicate your project further.

让我尝试解释CMake中的链接工作原理。这个想法是你在CMake中建立模块，并将它们链接在一起。现在让我们忽略头文件，因为它们都可以包含在源文件中。

Let me try to explain how linking works in CMake. The idea is that you build modules in CMake, and link them together. Let's ignore header files for now, as they can be all included in your source files.

假设你有file1.cpp，file2.cpp，main.cpp。您可以用以下方式将它们添加到项目中：

Say you have file1.cpp, file2.cpp, main.cpp. You add them to your project with:

ADD_LIBRARY(LibsModule 
    file1.cpp
    file2.cpp
)

现在您将它们添加到一个名为 LibsModule 。记住这一点。
例如，您想链接到 pthread ，例如已经在系统中。您可以使用以下命令将它与 LibsModule 结合使用：

Now you added them to a module called LibsModule. Keep that in mind. Say you want to link to pthread for example that's already in the system. You can combine it with LibsModule using the command:

target_link_libraries(LibsModule -lpthread)

如果你想链接一个静态库， / p>

And if you want to link a static library to that too, you do this:

target_link_libraries(LibsModule liblapack.a)

如果你想添加这些库所在目录，你可以：

And if you want to add a directory where any of these libraries are located, you do this:

target_link_libraries(LibsModule -L/home/user/libs/somelibpath/)

一个可执行文件，并将其与您的主文件链接：

Now you add an executable, and you link it with your main file:

ADD_EXECUTABLE(MyProgramExecBlaBla main.cpp)

（我添加BlaBla只是为了说明名称是自定义的）。然后，将 LibsModule 与您的可执行模块链接 MyProgramExecBlaBla

(I added BlaBla just to make it clear that the name is custom). And then you link LibsModule with your executable module MyProgramExecBlaBla

target_link_libraries(MyProgramExecBlaBla LibsModule)

我在CMake文件中看到的是很多冗余。例如，为什么你有 texture_mapping ，这是你的include目录中的可执行模块？所以你需要清理这一点，并遵循我解释的简单逻辑。希望它可以工作。

What I see in your CMake file is a lot of redundancy. For example, why do you have texture_mapping, which is an executable module in your include directories? So you need to clean this up and follow the simple logic I explained. Hopefully it works.

总之，它看起来像这样：

In summary, it looks like this:

project (MyProgramExecBlaBla)  #not sure whether this should be the same name of the executable, but I always see that "convention"
cmake_minimum_required(VERSION 2.8)

ADD_LIBRARY(LibsModule 
    file1.cpp
    file2.cpp
)

target_link_libraries(LibsModule -lpthread)
target_link_libraries(LibsModule liblapack.a)
target_link_libraries(LibsModule -L/home/user/libs/somelibpath/)
ADD_EXECUTABLE(MyProgramExecBlaBla main.cpp)
target_link_libraries(MyProgramExecBlaBla LibsModule)

最重要的是要理解的是模块结构，你可以创建模块并将它们与可执行文件连接在一起。一旦这个工作，你可以复杂化您的项目进一步与更多的细节。祝你好运！

The most important thing to understand is the module structure, where you create modules and link them all together with your executable. Once this works, you can complicate your project further with more details. Good luck!

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