install : https://www.cnblogs.com/yhcasey/p/15034052.html
github: https://github.com/protocolbuffers/protobuf
1 // g++ *.cc -o main -I /usr/local/protobuf/include/ -L /usr/local/protobuf/lib/libprotobuf.so.15 -lprotobuf -std=c++11 2 // protoc -I=<dir> --cpp_out=<dir> test.proto