CMake 链接器无法正常工作

Question

我正在尝试使用 CMake 构建我的项目，但在链接所需库时出错。我在项目的根文件夹中有这个 CMakeLists.txt：

cmake_minimum_required(VERSION 2.6)
project(test)
add_subdirectory(src)

在我的 src 文件夹中，在我的源文件旁边，我有这个 CMakeLists.txt：

set (CMAKE_CXX_FLAGS "Wall -std=c++11" )
set (CMAKE_EXE_LINKER_FLAGS "-lSDL2 -lGL" )
file (GLOB SRCS *.cpp *.h )
add_executable(engine ${SRCS} )

然后我进入构建文件夹并执行cmake ..，它运行时没有任何错误。当我做make 时，编译运行也没有任何错误，但是当它到达链接部分时，我得到了这些错误：

CMakeFiles/test.dir/Application.cpp.o: In function `Application::onExecute()':
Application.cpp:(.text+0x41): undefined reference to `SDL_GetTicks'
Application.cpp:(.text+0x4e): undefined reference to `SDL_GetTicks'
Application.cpp:(.text+0xd7): undefined reference to `SDL_PollEvent'
CMakeFiles/test.dir/Application.cpp.o: In function `Application::render()':
Application.cpp:(.text+0x17b): undefined reference to `glClearColor'
Application.cpp:(.text+0x185): undefined reference to `glClear'
Application.cpp:(.text+0x194): undefined reference to `SDL_GL_SwapWindow'
CMakeFiles/test.dir/Application.cpp.o: In function `Application::cleanUp()':
Application.cpp:(.text+0x1b2): undefined reference to `SDL_GL_DeleteContext'
Application.cpp:(.text+0x1c1): undefined reference to `SDL_DestroyWindow'
Application.cpp:(.text+0x1c6): undefined reference to `SDL_Quit'
CMakeFiles/test.dir/Application.cpp.o: In function `Application::initialize()':
Application.cpp:(.text+0x1de): undefined reference to `SDL_Init'
Application.cpp:(.text+0x1ea): undefined reference to `SDL_GetError'
Application.cpp:(.text+0x22b): undefined reference to `SDL_CreateWindow'
Application.cpp:(.text+0x243): undefined reference to `SDL_GetError'
Application.cpp:(.text+0x25a): undefined reference to `SDL_Quit'
Application.cpp:(.text+0x270): undefined reference to `SDL_GL_SetAttribute'
Application.cpp:(.text+0x27f): undefined reference to `SDL_GL_SetAttribute'
Application.cpp:(.text+0x28e): undefined reference to `SDL_GL_SetAttribute'
Application.cpp:(.text+0x29d): undefined reference to `SDL_GL_CreateContext'
Application.cpp:(.text+0x2af): undefined reference to `glGetString'
collect2: error: ld returned 1 exit status
make[2]: *** [src/test] Error 1
make[1]: *** [src/CMakeFiles/test.dir/all] Error 2
make: *** [all] Error 2

我的头文件中有正确的包含，并且我能够仅使用 make 编译和运行，所以我认为我告诉 CMake 的链接器标志没有被传递给编译器。我该如何解决这个问题？

Answer 1

您必须使用 cmake 命令 target_link_libraries 来引用 SDL 库。