key = (st.st_ino & 0xffff) | ((st.st_dev & 0xff) << 16) | (id << 24);
key = (st.st_ino & 0xffff) | ((st.st_dev & 0xff) << 16) | (proj_id << 24);
ftok (pathname, proj_id)     char *pathname;     char proj_id;{  struct stat st;  key_t key;  if (__stat (pathname, &st) < 0)    return (key_t) -1;  key = (st.st_ino & 0xffff) | ((st.st_dev & 0xff) << 16) | (id << 24);  return key;}