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- Will the 2nd -std=gnu++14 override the 1
Will the 2nd -std=gnu++14 override the 1st -std=c++17 ?
A naive concept question: while I'm building a file/folder, for instance, here, I'm trying to build protobuf from source, one of the building commands is:
[ 46%] Building CXX object CMakeFiles/libprotobuf.dir/src/google/protobuf/io/gzip_stream.cc.o
/usr/bin/c++ -DGOOGLE_PROTOBUF_CMAKE_BUILD -DHAVE_ZLIB -I....../protobuf/build -I....../protobuf/src -I....../protobuf/third_party/googletest/googlemock -I....../protobuf/third_party/googletest/googletest -I....../protobuf/third_party/googletest/googletest/include -I....../protobuf/third_party/googletest/googlemock/include -I....../protobuf/third_party/utf8_range -I....../protobuf/third_party/abseil-cpp -std=c++17 -fPIC -O3 -DNDEBUG -fvisibility=hidden -fvisibility-inlines-hidden -std=gnu++14 -o CMakeFiles/libprotobuf.dir/src/google/protobuf/io/gzip_stream.cc.o -c ....../protobuf/src/google/protobuf/io/gzip_stream.cc
Will the 2nd -std=gnu++14 override -std=c++17??
Thank you ...
The man gcc either does not mention, or hides the info from casual reader.
If https://stackoverflow.com/questions/52874345/is-gcc-flags-repetition-and-ordering-important is true, then the last occurrence wins.
You can test. Create minimal programs that depend on certain version. For example, with
A. -std=c++98 -std=c++14
B. -std=c++14 -std=c++98
Only one of those should succeed.
If https://stackoverflow.com/questions/52874345/is-gcc-flags-repetition-and-ordering-important is true, then the last occurrence wins.
You can test. Create minimal programs that depend on certain version. For example, with
auto in it. Then try both orders, e.g.A. -std=c++98 -std=c++14
B. -std=c++14 -std=c++98
Only one of those should succeed.
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