In file included from main.cpp:35:0:
buffered_reader.h: In member function 'int32_t BufferedReader::Read(char*, int32_t)':
buffered_reader.h:55:9: error: init-statement in selection statements only available with -std=c++1z or -std=gnu++1z [-Werror]
     if (auto len = _ostBuf.size(); len <= static_cast<size_t> (buffer_len)) {
         ^~~~
buffered_reader.h:59:15: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
       if (len == buffer_len) {
           ~~~~^~~~~~~~~~~~~
cc1plus: all warnings being treated as errors