+int para_select(int n, fd_set *readfds, fd_set *writefds,
+ struct timeval *timeout_tv);
+int mark_fd_nonblock(int fd);
+void para_fd_set(int fd, fd_set *fds, int *max_fileno);
+__must_check int para_fgets(char *line, int size, FILE *f);
+void *para_mmap(size_t length, int prot, int flags, int fd, off_t offset);
+int para_open(const char *path, int flags, mode_t mode);
+int para_opendir(const char *dirname, DIR **dir, int *cwd);
+int para_mkdir(const char *path, mode_t mode);
+int para_fchdir(int fd);