我对c++完全陌生(刚刚开始从头开始学习(。今天我的macos更新到了11.3，现在当我在clion中运行c++代码时，我收到了这个错误，
====================[ Build | untitled | Debug ]================================
/Applications/CLion.app/Contents/bin/cmake/mac/bin/cmake --build /Users/nibin/CLionProjects/untitled/cmake-build-debug --target untitled -- -j 6
[ 50%] Building CXX object CMakeFiles/untitled.dir/main.cpp.o
clang: warning: no such sysroot directory: '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk' [-Wmissing-sysroot]
In file included from /Users/nibin/CLionProjects/untitled/main.cpp:1:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/iostream:37:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ios:214:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/iosfwd:95:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/wchar.h:119:15: fatal error: 'wchar.h' file not found
#include_next <wchar.h>
^~~~~~~~~
1 error generated.
make[3]: *** [CMakeFiles/untitled.dir/main.cpp.o] Error 1
make[2]: *** [CMakeFiles/untitled.dir/all] Error 2
make[1]: *** [CMakeFiles/untitled.dir/rule] Error 2
make: *** [untitled] Error 2
我在网上搜索了一下，但一个字也听不懂。我确实尝试了一些，并在我的终端中得到了这个
➜ ~ xcode-select --install
xcode-select: error: command line tools are already installed, use "Software Update" to install updates
➜ ~ xcrun --show-sdk-path
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
➜ ~ sudo xcode-select --switch /Library/Developer/CommandLineTools/
Password:
➜ ~ xcrun --show-sdk-path
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk
我已经有xcode工具和它是最新的。我尝试了其中一个解决方案，那就是改变路径，但仍然没有成功。所以我只是把文件带回了原来的位置，
➜ ~ sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer/
➜ ~ xcrun --show-sdk-path
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
还有另一种解决方案，我尝试了一下，但出现了错误，
➜ ~ open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg
The file /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg does not exist.
我打开了/Library/Developer/CommandLineTools/，我得到了这个，
➜ ~ cd /Library/Developer/CommandLineTools
➜ CommandLineTools ls
Library SDKs usr
一些解决方案涉及清除高速缓存"；删除当前项目和依赖项中的任何旧CMakeCache.txt并重新生成解决了问题"很抱歉，如果这听起来很愚蠢，但我不太理解。这是否意味着我们必须删除整个文件CMakeCache.txt，还是只是内容。
"我们认为Tools | CMake | Reset Cache and Reload project在这种情况下应该有所帮助"(https://intellij-support.jetbrains.com/hc/en-us/community/posts/360000919219-Clion-can-t-compile-because-of-wchar-h-not-found-after-updated-Mojave-in-mac-)这对我很有效