In file included from main.cpp:35:0:
buffered_reader.h: In member function 'int32_t BufferedReader::Read(char*, int32_t)':
buffered_reader.h:24:51: error: unused variable 'res' [-Werror=unused-variable]
     int count = bytes / d->PackageLen(), len = 0, res;
                                                   ^~~
buffered_reader.h:38:1: error: control reaches end of non-void function [-Werror=return-type]
 }
 ^
cc1plus: all warnings being treated as errors