When using clang++, how can I make CMake use the -std=c++0x flag when compiling, but not when linking?
There are several other posts regarding using clang as compiler, but I have not found any hints on setting the c++ standard.
Here is what I tried:
CMakeLists.txt:
project(test)
add_executable(main main.cxx)
ClangOverride.txt:
SET (CMAKE_C_FLAGS_INIT "-Wall -std=c99")
SET (CMAKE_C_FLAGS_DEBUG_INIT "-g")
SET (CMAKE_C_FLAGS_MINSIZEREL_INIT "-Os -DNDEBUG")
SET (CMAKE_C_FLAGS_RELEASE_INIT "-O3 -DNDEBUG")
SET (CMAKE_C_FLAGS_RELWITHDEBINFO_INIT "-O2 -g")
SET (CMAKE_CXX_FLAGS_INIT "-Wall -std=c++0x -stdlib=libc++")
SET (CMAKE_CXX_FLAGS_DEBUG_INIT "-g")
SET (CMAKE_CXX_FLAGS_MINSIZEREL_INIT "-Os -DNDEBUG")
SET (CMAKE_CXX_FLAGS_RELEASE_INIT "-O3 -DNDEBUG")
SET (CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "-O2 -g")
SET (CMAKE_EXE_LINKER_FLAGS_INIT "")
main.cxx:
int main(){ return 0; }
Command used to invoke cmake
CC=clang CXX=clang++ cmake .. -DCMAKE_USER_MAKE_RULES_OVERRIDE=ClangOverride.txt -DCMAKE_BUILD_TYPE=Release
Building the project:
VERBOSE=1 make
This will invoke the following two commands:
/usr/bin/clang++ -Wall -std=c++0x -stdlib=libc++ -O3 -DNDEBUG -o CMakeFiles/main.dir/main.cxx.o -c /tmp/asdf/main.cxx
/usr/bin/clang++ -Wall -std=c++0x -stdlib=libc++ -O3 -DNDEBUG CMakeFiles/main.dir/main.cxx.o -o main -rdynamic
The second command results in warning because if the un-used flag: -std=c++0x
clang: warning: argument unused during compilation: '-std=c++0x'
CMakeFiles/main.dir/main.cxx.o: file not recognized: File format not recognized
clang: error: linker command failed with exit code 1 (use -v to see invocation)
How can I avoid this?
