clang++ -E -x c++ - -v < /dev/null
Apple clang version 12.0.0 (clang-1200.0.32.29)
Target: x86_64-apple-darwin19.6.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include/c++/v1"
 "/Library/Developer/CommandLineTools/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.15.0 -Wdeprecated-objc-isa-usage -Werror=deprecated-objc-isa-usage -Werror=implicit-function-declaration -E -disable-free -disable-llvm-verifier -discard-value-names -main-file-name - -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=all -fno-strict-return -masm-verbose -munwind-tables -target-sdk-version=10.15.6 -fcompatibility-qualified-id-block-type-checking -target-cpu penryn -dwarf-column-info -debugger-tuning=lldb -target-linker-version 609.8 -v -resource-dir /Library/Developer/CommandLineTools/usr/lib/clang/12.0.0 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk -I/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain -I/usr/local/include -stdlib=libc++ -internal-isystem /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1 -internal-isystem /Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/local/include -internal-isystem /Library/Developer/CommandLineTools/usr/lib/clang/12.0.0/include -internal-externc-isystem /Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include -internal-externc-isystem /Library/Developer/CommandLineTools/usr/include -Wno-reorder-init-list -Wno-implicit-int-float-conversion -Wno-c99-designator -Wno-final-dtor-non-final-class -Wno-extra-semi-stmt -Wno-misleading-indentation -Wno-quoted-include-in-framework-header -Wno-implicit-fallthrough -Wno-enum-enum-conversion -Wno-enum-float-conversion -fdeprecated-macro -fdebug-compilation-dir /Library/Developer/CommandLineTools/SDKs -ferror-limit 19 -fmessage-length 87 -stack-protector 1 -fstack-check -mdarwin-stkchk-strong-link -fblocks -fencode-extended-block-signature -fregister-global-dtors-with-atexit -fgnuc-version=4.2.1 -fobjc-runtime=macosx-10.15.0 -fcxx-exceptions -fexceptions -fmax-type-align=16 -fdiagnostics-show-option -fcolor-diagnostics -o - -x c++ -
clang -cc1 version 12.0.0 (clang-1200.0.32.29) default target x86_64-apple-darwin19.6.0
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/local/include"
ignoring nonexistent directory "/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/Library/Frameworks"
#include "..." search starts here:
#include <...> search starts here:
 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain
 /usr/local/include
 /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1
 /Library/Developer/CommandLineTools/usr/lib/clang/12.0.0/include
 /Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include
 /Library/Developer/CommandLineTools/usr/include
 /Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/System/Library/Frameworks (framework directory)
End of search list.
# 1 "<stdin>"
# 1 "<built-in>" 1
# 1 "<built-in>" 3
# 379 "<built-in>" 3
# 1 "<command line>" 1
# 1 "<built-in>" 2
# 1 "<stdin>" 2