1  /* Copyright (C) 1995-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <sys/ipc.h>
      19  #include <sys/stat.h>
      20  
      21  key_t
      22  ftok (const char *pathname, int proj_id)
      23  {
      24    struct __stat64_t64 st;
      25    key_t key;
      26  
      27    if (__stat64_time64 (pathname, &st) < 0)
      28      return (key_t) -1;
      29  
      30    key = ((st.st_ino & 0xffff) | ((st.st_dev & 0xff) << 16)
      31  	 | ((proj_id & 0xff) << 24));
      32  
      33    return key;
      34  }