SDL2 Cmake 未定义对 Win10 MinGW 上的“WinMain@16”的引用答案

【问题标题】：SDL2 Cmake undefined reference to `WinMain@16' on Win10 MinGWSDL2 Cmake 未定义对 Win10 MinGW 上的“WinMain@16”的引用
【发布时间】：2020-03-31 10:47:50
【问题描述】：

我正在尝试使用 MinGW 在 CLion 中设置 SDL，但是我在错误之后得到错误，我无法想象我哪里出错了。现在我有了这个 Cmake 代码，我得到了错误 undefined reference to 'WinMain@16' 。我想我忘了链接一些东西，可能是 SDLmain，但我想我是在 target_link_libraries() 那里写的。我将不胜感激一些帮助，使其工作。

cmake_minimum_required(VERSION 3.15)
project(SDL_project)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIR})

add_executable(SDL_project main.cpp)

target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARY} -lmingw32 -lSDL2main -lSDL2 -mwindows)

错误信息：

    ====================[ Build | SDL_project | Debug ]=============================
"A:\CLion 2019.2.5\bin\cmake\win\bin\cmake.exe" --build D:\SDL_project\cmake-build-debug --target SDL_project -- -j 4
Scanning dependencies of target SDL_project
[ 50%] Building CXX object CMakeFiles/SDL_project.dir/main.cpp.obj
[100%] Linking CXX executable SDL_project.exe
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/lib/../lib/libmingw32.a(lib32_libmingw32_a-crt0_c.o): in function `main':
D:/mingwbuild/mingw-w64-crt-git/src/mingw-w64/mingw-w64-crt/crt/crt0_c.c:18: undefined reference to `WinMain@16'
collect2.exe: error: ld returned 1 exit status
CMakeFiles\SDL_project.dir\build.make:86: recipe for target 'SDL_project.exe' failed
CMakeFiles\Makefile2:74: recipe for target 'CMakeFiles/SDL_project.dir/all' failed
CMakeFiles\Makefile2:81: recipe for target 'CMakeFiles/SDL_project.dir/rule' failed
mingw32-make.exe[3]: *** [SDL_project.exe] Error 1
mingw32-make.exe[2]: *** [CMakeFiles/SDL_project.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles/SDL_project.dir/rule] Error 2
mingw32-make.exe: *** [SDL_project] Error 2
Makefile:117: recipe for target 'SDL_project' failed

而且我还在项目文件夹中做了一个cmake文件夹，供SDL查找，但不确定是否有必要。

set(FIND_SDL2_PATHS D:/SDL2/SDL2-devel-2.0.12-mingw/SDL2-2.0.12/x86_64-w64-mingw32)

find_path(SDL2_INCLUDE_DIR SDL2
        PATH_SUFFIXES include
        PATHS ${FIND_SDL2_PATHS})

find_library(SDL2_LIBRARY
        NAMES SDL2
        PATH_SUFFIXES lib
        PATHS ${FIND_SDL2_PATHS})

【问题讨论】：

请复制粘贴错误消息到问题帖子中作为文本，而不是图像。这是堆栈溢出的要求。另请参阅How to Ask。
顺便说一句，您已经按照that answer 中的描述定义了SDL_MAIN_HANDLED 宏，不是吗？

标签： cmake mingw static-libraries clion

【解决方案1】：

解决方案是在末尾添加一个新行：add_definitions(-DSDL_MAIN_HANDLED)。

现在 CMakeLists.txt 代码如下所示：

cmake_minimum_required(VERSION 3.15)
project(SDL_project)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIR})

add_executable(SDL_project main.cpp)

target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARY} -lmingw32 -mwindows)
add_definitions(-DSDL_MAIN_HANDLED)

在名为cmake 的单独文件夹中的项目文件夹中有FindSDL2.cmake 文件，用于定位SDL2：

set(FIND_SDL2_PATHS D:/SDL2/SDL2-devel-2.0.12-mingw/SDL2-2.0.12/x86_64-w64-mingw32)

find_path(SDL2_INCLUDE_DIR SDL2
        PATH_SUFFIXES include
        PATHS ${FIND_SDL2_PATHS})

find_library(SDL2_LIBRARY
        NAMES SDL2 SDL2main
        PATH_SUFFIXES lib
        PATHS ${FIND_SDL2_PATHS})

我从 CMakeLists.txt 中删除了 -lSDL2 和 -lSDL2main 标志，因为它们会导致错误：

====================[ Build | SDL_project | Debug ]=============================
"A:\CLion 2019.2.5\bin\cmake\win\bin\cmake.exe" --build D:\SDL_project\cmake-build-debug --target SDL_project -- -j 4
[ 50%] Linking CXX executable SDL_project.exe
A:/MSYS2/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/9.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: cannot find -lSDL2
A:/MSYS2/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/9.3.0/../../../../x86_64-w64-mingw32/bin/ld.exe: cannot find -lSDL2main
collect2.exe: error: ld returned 1 exit status
CMakeFiles\SDL_project.dir\build.make:86: recipe for target 'SDL_project.exe' failed
CMakeFiles\Makefile2:74: recipe for target 'CMakeFiles/SDL_project.dir/all' failed
CMakeFiles\Makefile2:81: recipe for target 'CMakeFiles/SDL_project.dir/rule' failed
Makefile:117: recipe for target 'SDL_project' failed
mingw32-make.exe[3]: *** [SDL_project.exe] Error 1
mingw32-make.exe[2]: *** [CMakeFiles/SDL_project.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles/SDL_project.dir/rule] Error 2
mingw32-make.exe: *** [SDL_project] Error 2

另外，使用 64 位的 mingw-w64 也很重要，因为 mingw-w32 也会报错，比如：

====================[ Build | SDL_project | Debug ]=============================
"A:\CLion 2019.2.5\bin\cmake\win\bin\cmake.exe" --build D:\SDL_project\cmake-build-debug --target SDL_project -- -j 4
[ 50%] Linking CXX executable SDL_project.exe
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: CMakeFiles\SDL_project.dir/objects.a(main.cpp.obj):D:/SDL_project/main.cpp:17: undefined reference to `SDL_Init'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: CMakeFiles\SDL_project.dir/objects.a(main.cpp.obj): in function `main':
D:/SDL_project/main.cpp:19: undefined reference to `SDL_GetError'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:24: undefined reference to `SDL_CreateWindow'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:27: undefined reference to `SDL_GetError'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:32: undefined reference to `SDL_GetWindowSurface'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:35: undefined reference to `SDL_MapRGB'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:35: undefined reference to `SDL_FillRect'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:38: undefined reference to `SDL_UpdateWindowSurface'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:41: undefined reference to `SDL_Delay'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:45: undefined reference to `SDL_DestroyWindow'
A:/MSYS2/mingw32/bin/../lib/gcc/i686-w64-mingw32/9.3.0/../../../../i686-w64-mingw32/bin/ld.exe: D:/SDL_project/main.cpp:48: undefined reference to `SDL_Quit'
collect2.exe: error: ld returned 1 exit status
CMakeFiles\SDL_project.dir\build.make:86: recipe for target 'SDL_project.exe' failed
CMakeFiles\Makefile2:74: recipe for target 'CMakeFiles/SDL_project.dir/all' failed
CMakeFiles\Makefile2:81: recipe for target 'CMakeFiles/SDL_project.dir/rule' failed
Makefile:117: recipe for target 'SDL_project' failed
mingw32-make.exe[3]: *** [SDL_project.exe] Error 1
mingw32-make.exe[2]: *** [CMakeFiles/SDL_project.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles/SDL_project.dir/rule] Error 2
mingw32-make.exe: *** [SDL_project] Error 2

而且，必须将二进制文件夹中的 SDL.dll 文件添加到编译器，以避免出现exit code -1073741515 (0xC0000135)。可以通过设置文件夹路径，或将 SDL.dll 从 SDL\bin 文件夹复制到 mingw64\bin 文件夹来完成。

【讨论】：