ftok.c

来自「用于嵌入式Linux系统的标准C的库函数」· C语言 代码 · 共 48 行

/* Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <[e-mail]>, August 1995.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

/* Modified for newlib by Jeff Johnston, June 10/2002 */

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/stat.h>

#if !defined(_ELIX_LEVEL) || _ELIX_LEVEL >= 2
#define STAT stat64
#else
#define STAT stat
#endif

key_t
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;
}