Clang 为什么叮当声产生了；“未使用的参数”；警告-nostinc++；用于可执行文件，但不用于库

我需要使用自定义libc++所以我将-nostinc++传递给CMAKE_CXX_标志。这对于库很好，但对于可执行文件，我得到以下警告：

clang: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]

问题：为什么

更多详细信息

传递给编译器的我的CMAKE_CXX_标志为：

set(CMAKE_CXX_FLAGS "-nostdinc++ -isystem ${LIBCXX_INC_PATH}")

我的CMAKE_EXE_链接器_标志传递给链接器的标志为：

set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -stdlib=libc++ -lc++ -lc++abi -lm -lc -lgcc_s -lgcc -ldl -Wl,-rpath,${LIBCXX_LIB_PATH}")

铿锵verbos输出：

Scanning dependencies of target DroneServer
[ 98%] Building CXX object DroneServer/CMakeFiles/DroneServer.dir/home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp.o
clang version 3.9.1-4ubuntu3~16.04.1 (tags/RELEASE_391/rc2)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.0.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
 "/usr/lib/llvm-3.9/bin/clang" -cc1 -triple x86_64-pc-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -discard-value-names -main-file-name main.cpp -mrelocation-model pic -pic-level 2 -pic-is-pie -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -v -dwarf-column-info -debug-info-kind=limited -dwarf-version=4 -debugger-tuning=gdb -coverage-file /home/shitals/GitHubSrc/AirSim/build_debug/DroneServer/CMakeFiles/DroneServer.dir/home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp.o -nostdinc++ -resource-dir /usr/lib/llvm-3.9/bin/../lib/clang/3.9.1 -isystem /home/shitals/GitHubSrc/AirSim/llvm-build/output/include/c++/v1 -I /home/shitals/GitHubSrc/AirSim/eigen/eigen3 -I /home/shitals/GitHubSrc/AirSim/DroneServer -I /home/shitals/GitHubSrc/AirSim/MavLinkCom/include -I /home/shitals/GitHubSrc/AirSim/external/rpclib/include -I /home/shitals/GitHubSrc/AirSim/AirLib/include -D __CLANG__ -D MSGPACK_PP_VARIADICS_MSVC=0 -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-3.9/bin/../lib/clang/3.9.1/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -Wall -Wextra -Wstrict-aliasing -Wunreachable-code -Wcast-qual -Wctor-dtor-privacy -Wdisabled-optimization -Wformat=2 -Winit-self -Wmissing-include-dirs -Wswitch-default -Wold-style-cast -Woverloaded-virtual -Wredundant-decls -Wshadow -Wstrict-overflow=5 -Wswitch-default -Wundef -Wno-variadic-macros -Wno-parentheses -Wno-unused-function -Wno-unused -Wno-documentation -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /home/shitals/GitHubSrc/AirSim/build_debug/DroneServer -ferror-limit 10 -fmessage-length 286 -pthread -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o CMakeFiles/DroneServer.dir/home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp.o -x c++ /home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp
clang -cc1 version 3.9.1 based upon LLVM 3.9.1 default target x86_64-pc-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /home/shitals/GitHubSrc/AirSim/eigen/eigen3
 /home/shitals/GitHubSrc/AirSim/DroneServer
 /home/shitals/GitHubSrc/AirSim/MavLinkCom/include
 /home/shitals/GitHubSrc/AirSim/external/rpclib/include
 /home/shitals/GitHubSrc/AirSim/AirLib/include
 /home/shitals/GitHubSrc/AirSim/llvm-build/output/include/c++/v1
 /usr/local/include
 /usr/lib/llvm-3.9/bin/../lib/clang/3.9.1/include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
[100%] Linking CXX executable ../output/bin/DroneServer
clang version 3.9.1-4ubuntu3~16.04.1 (tags/RELEASE_391/rc2)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.0.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
clang: warning: argument unused during compilation: '-nostdinc++' [-Wunused-command-line-argument]
 "/usr/bin/ld" -z relro --hash-style=gnu --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o ../output/bin/DroneServer /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../x86_64-linux-gnu/crt1.o /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../x86_64-linux-gnu/crti.o /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/crtbegin.o -L/usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0 -L/usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../x86_64-linux-gnu -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../.. -L/usr/lib/llvm-3.9/bin/../lib -L/lib -L/usr/lib -lc++ -lc++abi -lm -lc -lgcc_s -lgcc -ldl -rpath /home/shitals/GitHubSrc/AirSim/llvm-build/output/lib CMakeFiles/DroneServer.dir/home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp.o -lpthread ../output/lib/libAirLib.a ../output/lib/libMavLinkCom.a ../output/lib/libAirSim-rpclib.a -lpthread -lpthread -lc++ -lm -lgcc_s -lgcc -lpthread -lc -lgcc_s -lgcc /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/crtend.o /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../x86_64-linux-gnu/crtn.o
[100%] Built target DroneServer

扫描目标服务器的依赖项
[98%]构建CXX对象DroneServer/cmakfiles/DroneServer.dir/home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp.o
clang版本3.9.1-4ubuntu3~16.04.1（标签/发布号\u 391/rc2）
目标：x86_64-pc-linux-gnu
线程模型：posix
已安装dir:/usr/bin
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/5
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/5.4.0
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/6
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/6.0.0
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/5
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/5.4.0
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/6
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/6.0.0
所选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/5.4.0
候选多重库：@m64
所选多库：@m64
“/usr/lib/llvm-3.9/bin/clang”-cc1-triple x86_64-pc-linux-gnu-emit obj-mrelax all-disable free-disable llvm verifier-discard value names-main.cpp-mrelocation model pic-pic level 2-pic is pie-mthread model posix-mdisable fp elim-fmath errno-masm verbose-mconstructor别名-munwind tables-fuse init array-target cpu x86-64-v-dwark列信息-debug info kind=limited-dwarf version=4-debugger tuning=gdb-coverage file/home/shitals/GitHubSrc/AirSim/build_debug/DroneServer/CMakeFiles/DroneServer.dir/home/shitals/GitHubSrc/AirSim/DroneServer/main.cpp.o-nostinc++-resource dir/usr/lib/llvm-3.9/bin//lib/clang/3.9.1-isystem/home/shitals/GitHubSrc/AirSim/llvm build/output/include/c++/v1-I/home/shitals/GitHubSrc/AirSim/eigen3-I/home/shitals/GitHubSrc/AirSim/DroneServer-I/home/shitals/GitHubSrc/AirSim/MavLinkCom/include-I/home/shitals/GitHubSrc/AirSim/AirSim/external/rpclib/include-DMSGPACK\u PP\u VARIADICS\u MSVC=0-内部isystem/usr/local/include-内部isystem/usr/lib/llvm-3.9/bin//lib/clang/3.9.1/include-内部外部isystem/usr/include/x86\u 64-linux-gnu-内部外部isystem/include-内部外部isystem/usr/include-Wall-Wextra-Wstrict别名-Wunreachable代码-Wcast-qual-Wctor dtor隐私-Wdisabled optimization-Wformat=2-Winit self-Wmissing include dirs-Wswitch default-Wold style cast-Woverloaded virtual-Wredundant decls-Wshadow-Wstrict overflow=5-Wswitch default-Wundef-Wno variadic macros-Wno圆括号-Wno unused function-Wno unused-Wno-Wno-Wno documentation-std=c++=14-fdeprecated宏-fdebug编译dirFor限制长度10 - FTER长度286 - pToC++ -fObcRunTime= GCC-FCXX例外- fCutoType显示选项-FCKORKECT/DRONEVER。DR/HONT/SHITALS/GITHUBSRC/AIR S/DRUNSERVER／MUCP.CP-O-XC++/HOST/SHITALS/GITHUBSRC/AIR S/DRUNSERVER /MIN
clang-cc1版本3.9.1基于LLVM 3.9.1默认目标x86_64-pc-linux-gnu
忽略不存在的目录“/包括”
#包括“…”搜索从这里开始：
#包括搜索从这里开始：
/home/shitals/GitHubSrc/AirSim/eigen/eigen3
/home/shitals/GitHubSrc/AirSim/drone服务器
/home/shitals/GitHubSrc/AirSim/MavLinkCom/include
/主页/shitals/GitHubSrc/AirSim/external/rpclib/include
/home/shitals/GitHubSrc/AirSim/AirLib/include
/home/shitals/GitHubSrc/AirSim/llvm build/output/include/c++/v1
/usr/本地/包括
/usr/lib/llvm-3.9/bin/。/lib/clang/3.9.1/include
/usr/include/x86_64-linux-gnu
/usr/包括
搜索列表结束。
[100%]链接CXX可执行文件../output/bin/server
clang版本3.9.1-4ubuntu3~16.04.1（标签/发布号\u 391/rc2）
目标：x86_64-pc-linux-gnu
线程模型：posix
已安装dir:/usr/bin
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/5
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/5.4.0
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/6
找到候选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/6.0.0
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/5
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/5.4.0
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/6
找到候选GCC安装：/usr/lib/GCC/x86_64-linux-gnu/6.0.0
所选GCC安装：/usr/bin/。/lib/GCC/x86_64-linux-gnu/5.4.0
候选多重库：@m64
所选多库：@m64
叮当声：警告：编译期间未使用的参数：'-nostdinc++'[-Wunused命令行参数]
“/usr/bin/ld”-z relro--hash style=gnu--eh frame hdr-m elf_x86_64-dynamic linker/lib64/ld-linux-x86-64.so.2-o../output/bin/DroneServer/usr/bin/。/lib/gcc/x86_64-linux-gnu/5.4.0/../../../x86_64-linux-gnu/crt1.o/usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../../x8664-linux-gnu/crt1.0/../../../../gr-L/usr/bin/。/lib/gcc/x86_64-linux-gnu/5.4.0-L/usr/bin/。/lib/gcc/x86_64-linux-gnu/5.4.0/。/../x86_64-linux-gnu-L/lib/x86_64-linux-gnu-L/lib64-L/usr/lib/x86_64-linux-gnu-L/usr/bin/../lib/gcc/x86-linux-gnu/5.4.0/../-L/usr/lib/llvm-3.9/bin/。/lib-L/lib-L/usr/lib-lc++-lc++abi-lm-lc-lgcc_-lgcc-ldl-rpath/home/shitals/GitHubSrc/AirSim/llvm build/output/lib CMakeFiles/DroneServer.dir/home/shitals/GitHubSrc/DroneServer/main.cpp.o-lpthread../output/lib/libAirLib.a../output/li