if (__stat (pathname, &st) < 0)
if (__xstat (_STAT_VER, pathname, &st) < 0)
ftok (pathname, proj_id)     const char *pathname;     int 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)	 | ((proj_id & 0xff) << 24));  return key;}