当我想通过 mingw(最新版本)使用带有 SFML 库的 CMake 来编译项目时,我发现了很多奇怪的错误(c++)。
CMake代码:
cmake_minimum_required(VERSION 3.0)
project(MLproject)
SET(CMAKE_SYSTEM_NAME Windows)
SET(CMAKE_SYSTEM_VERSION 1)
SET(CMAKE_C_COMPILER "i686-w64-mingw32-gcc")
SET(CMAKE_CXX_COMPILER "i686-w64-mingw32-g++")
SET(CMAKE_RC_COMPILER "i686-w64-mingw32-windres")
SET(CMAKE_RANLIB "i686-w64-mingw32-ranlib")
set(CMAKE_CXX_STANDARD 17)
SET(CMAKE_FIND_ROOT_PATH "/usr/i686-w64-mingw32")
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(SOURCE_EXE src/main.cpp)
set(SOURCE_GAME
src/Boss/Boss.cpp
*...*
src/Game/Game.cpp)
set(SOURCE_UI
src/UI/ScrollBar/ScrollBar.cpp)
add_library(UI SHARED ${SOURCE_UI})
add_library(Game SHARED ${SOURCE_GAME})
add_executable(main ${SOURCE_EXE})
target_link_libraries(main Game UI
sfml-graphics sfml-system sfml-windos sfml-audio)
错误:
CMakeFiles/UI.dir/src/UI/ScrollBar/ScrollBar.cpp.o:ScrollBar.cpp:(.text+0x6d): undefined reference to `_imp___ZN2sf14RectangleShapeC1ERKNS_7Vector2IfEE'
CMakeFiles/UI.dir/src/UI/ScrollBar/ScrollBar.cpp.o:ScrollBar.cpp:(.text+0x399): undefined reference to `_imp___ZN2sf12RenderStates7DefaultE.....
我该如何修复它?我是否因为 C++ 版本太旧而捕获错误? (一切都为Linux编译成功,但我想做跨平台)
错误:
CMakeFiles/UI.dir/src/UI/ScrollBar/ScrollBar.cpp.o:ScrollBar.cpp:(.text+0x6d): undefined reference to `_imp___ZN2sf14RectangleShapeC1ERKNS_7Vector2IfEE'
表示
UI
库使用一些 SFML 组件。但是,您仅将 SFML 库链接到 main
可执行文件,因此该库不知道这些 SFML 引用是在哪里定义的。因此,您必须将任何相关的 SFML 库链接到 UI
目标:
target_link_libraries(UI PUBLIC sfml-graphics sfml-system sfml-windos sfml-audio)
在此处使用
PUBLIC
将 SFML 库传播到 UI
目标的 consumers,例如您的
main
可执行文件。这样就不需要将它们显式链接到 main
。这是包含这些更改的完整 CMake:
cmake_minimum_required(VERSION 3.0)
project(MLproject)
# As commented, consider moving these calls to your toolchain file.
SET(CMAKE_SYSTEM_NAME Windows)
SET(CMAKE_SYSTEM_VERSION 1)
SET(CMAKE_C_COMPILER "i686-w64-mingw32-gcc")
SET(CMAKE_CXX_COMPILER "i686-w64-mingw32-g++")
SET(CMAKE_RC_COMPILER "i686-w64-mingw32-windres")
SET(CMAKE_RANLIB "i686-w64-mingw32-ranlib")
SET(CMAKE_FIND_ROOT_PATH "/usr/i686-w64-mingw32")
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_CXX_STANDARD 17)
set(SOURCE_EXE src/main.cpp)
set(SOURCE_GAME
src/Boss/Boss.cpp
*...*
src/Game/Game.cpp)
set(SOURCE_UI
src/UI/ScrollBar/ScrollBar.cpp)
add_library(UI SHARED ${SOURCE_UI})
# Link SFML libraries to UI.
target_link_libraries(UI PUBLIC sfml-graphics sfml-system sfml-windos sfml-audio)
add_library(Game SHARED ${SOURCE_GAME})
add_executable(main ${SOURCE_EXE})
# Link Game and UI to the executable, which propagates the SFML libraries from UI also.
target_link_libraries(main PRIVATE Game UI)
请注意,CMake 顶部的许多调用都属于工具链文件(如注释所示),通常用于交叉编译。我鼓励您通读文档以确定您的需要,并了解如何设置它。
将
_imp___ZN2sf14RectangleShapeC1ERKNS_7Vector2IfEE
添加到 cflags 后,问题就消失了 -DSFML_STATIC
。
C++ 根据源代码为链接器创建这些“神秘”的名称,即所谓的“名称修改”,因此链接时出现了宏切换问题
SFML_STATIC
。