int fdatasync(int fildes);
int lstat(const char * path, struct stat * buf);
uid_t geteuid(void);
+char* ctime_r(const time_t *t, char *buf);
int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
ssize_t pread(int fildes, void *buf, size_t nbyte, off_t offset);
ssize_t pwrite(int fildes, const void *buf, size_t nbyte,