in main.cpp
bool ret = config_manager::from_file(cfg, "./cfg/feather.cfg");

returns false. I have to use a absolute path to the file or ../cfg/feather.cfg then it succeeds

after that the "init" function throws:
terminate called after throwing an instance of 'std::invalid_argument'
what(): init failed
Aborted (core dumped)

when calling
dao_t<dbng>::init(cfg.db_conn_num, cfg.db_ip.data(), cfg.user_name.data(), cfg.pwd.data(),
cfg.db_name.data(), cfg.timeout);

what could fix this issue?
compiler g++ 7.3.0
operating system ubuntu