__must_check int mark_fd_nonblocking(int fd);
__must_check int mark_fd_blocking(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);