add daemon(1,0) ,then log is missing

[bolanbujing]

if(daemon(1, 0) < 0){
std::cout << "deamon fail"<< std::endl;
return 0;
}
gflags::ParseCommandLineFlags(&argc, &argv, true);
google::InitGoogleLogging(argv[0]);
google::InstallFailureSignalHandler();
mkdir("./log", S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
//google::SetLogDestination(google::GLOG_INFO, "./log/");
FLAGS_alsologtostderr = false;
FLAGS_log_dir = "./log";
FLAGS_logbufsecs = 0;
LOG(INFO) << "HELOO";
LOG(INFO) << "11111";
LOG(INFO) << "22222";
LOG(INFO) << "33333";
LOG(INFO) << "44444";

execute and the result is that log after the 'HELOO' is missing, only left with 'HELOO'