c++ - 为什么cmake还为导入的软件包添加了编译选项？

我有一个需要一些依赖项的项目，并且使用vcpkg来管理它们。现在，我想为我的可执行文件和子目录使用add_compile_options( /W4 /WX /std:c++17 )设置编译选项，但我不希望将它们应用于已装载find_package的软件包。

这是测试库中CMakeLists.txt中的代码：

cmake_minimum_required(VERSION 3.15)
project(test)

set(VCPKG_DEPENDENCIES glm)

# set the build triplet for windows because default is x86-windows
if(WIN32)
    set(VCPKG_TARGET_TRIPLET "x64-windows")
    add_compile_options( /W4 /WX /std:c++17 )
endif()

get_filename_component(ABS_PATH_VCPKG "./vcpkg" REALPATH)
set(VCPKG_ROOT ${ABS_PATH_VCPKG})
set(CMAKE_TOOLCHAIN_FILE "${ABS_PATH_VCPKG}/scripts/buildsystems/vcpkg.cmake")
# additional folder where find_XXXX functions are searching for packages
set(CMAKE_PREFIX_PATH "${VCPKG_ROOT}/installed/${VCPKG_TARGET_TRIPLET}/share")

foreach(DEPENDENCY ${VCPKG_DEPENDENCIES})
    message(STATUS "installing vcpkg dependency: <${DEPENDENCY}>")
    execute_process(COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/vcpkg/vcpkg.exe install ${DEPENDENCY}:${VCPKG_TARGET_TRIPLET} OUTPUT_FILE ${CMAKE_CURRENT_SOURCE_DIR}/vcpkg_install_log.txt)
endforeach()

add_executable(test main.cpp)

find_package(glm CONFIG REQUIRED)
target_link_libraries(test PRIVATE glm)

答：这是我的主要任务：

#include <iostream>
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>

int main()
{
    glm::vec3 vec(1.0);
    std::cout << ("Hello World!");
    return 0;
}

但是，glm软件包正在使用add_library键调用IMPORTED，这应该通知该软件包是系统软件包，并且不应获取应用到的选项。

这是错误代码：

[build] Starting build
[proc] Executing command: "C:\Program Files\CMake\bin\cmake.EXE" --build <path>/cpp_test_Isystem/build --config Debug --target all -- -j 18
[build] [1/2  50% :: 0.752] Building CXX object CMakeFiles\test.dir\main.cpp.obj
[build] FAILED: CMakeFiles/test.dir/main.cpp.obj
[build] <path>\VC\Tools\MSVC\1423~1.281\bin\Hostx64\x64\cl.exe  /nologo /TP  -I..\vcpkg\installed\x64-windows\include /DWIN32 /D_WINDOWS /GR /EHsc /Zi /Ob0 /Od /RTC1 -MDd   /W4 /WX /std:c++17 /showIncludes /FoCMakeFiles\test.dir\main.cpp.obj /FdCMakeFiles\test.dir\ /FS -c ..\main.cpp
[build] <path>\cpp_test_Isystem\vcpkg\installed\x64-windows\include\glm\ext\../detail/type_quat.hpp(58): error C2220: the following warning is treated as an error
[build] <path>\cpp_test_Isystem\vcpkg\installed\x64-windows\include\glm\ext\../detail/type_quat.hpp(137): note: see reference to class template instantiation 'glm::qua<T,Q>' being compiled
[build] <path>\cpp_test_Isystem\vcpkg\installed\x64-windows\include\glm\ext\../detail/type_quat.hpp(58): warning C4201: nonstandard extension used: nameless struct/union
[build] ninja: build stopped: subcommand failed.
[build] Build finished with exit code 1

最佳答案

您的main.cpp文件包含此头，因此适用于该文件的所有选项也将应用于该头。

您的选择：


在GLM标头的#pragma周围使用#include禁用C4201警告：

#pragma warning( push )
#pragma warning( disable : 4201 )
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>
#pragma warning( pop )

禁用来自CMake的警告：

target_add_compile_options(test /wd4201)

编辑：使用特定于GLM的定义使这些警告（source）保持沉默：

#define GLM_FORCE_SILENT_WARNINGS

（或等效于target_add_definitions）

关于c++ - 为什么cmake还为导入的软件包添加了编译选项？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/58875800/