File: /usr/include/sys/sysmacros.h

1     /* Definitions of macros to access `dev_t' values.
2        Copyright (C) 1996, 1997, 1999 Free Software Foundation, Inc.
3        This file is part of the GNU C Library.
4     
5        The GNU C Library is free software; you can redistribute it and/or
6        modify it under the terms of the GNU Library General Public License as
7        published by the Free Software Foundation; either version 2 of the
8        License, or (at your option) any later version.
9     
10        The GNU C Library is distributed in the hope that it will be useful,
11        but WITHOUT ANY WARRANTY; without even the implied warranty of
12        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13        Library General Public License for more details.
14     
15        You should have received a copy of the GNU Library General Public
16        License along with the GNU C Library; see the file COPYING.LIB.  If not,
17        write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18        Boston, MA 02111-1307, USA.  */
19     
20     #ifndef _SYS_SYSMACROS_H
21     #define _SYS_SYSMACROS_H	1
22     
23     /* For compatibility we provide alternative names.
24     
25        The problem here is that compilers other than GCC probably don't
26        have the `long long' type and so `dev_t' is actually an array.  */
27     #if defined __GNUC__ && __GNUC__ >= 2
28     # define major(dev) ((int)(((dev) >> 8) & 0xff))
29     # define minor(dev) ((int)((dev) & 0xff))
30     # define makedev(major, minor) ((((unsigned int) (major)) << 8) \
31     				| ((unsigned int) (minor)))
32     #else
33     /* We need to know the word order here.  This assumes that the word order
34        is consistent with the byte order.  */
35     # include <endian.h>
36     # if __BYTE_ORDER == __BIG_ENDIAN
37     #  define major(dev) (((dev).__val[1] >> 8) & 0xff)
38     #  define minor(dev) ((dev).__val[1] & 0xff)
39     #  define makedev(major, minor) { 0, ((((unsigned int) (major)) << 8) \
40     				      | ((unsigned int) (minor))) }
41     # else
42     #  define major(dev) (((dev).__val[0] >> 8) & 0xff)
43     #  define minor(dev) ((dev).__val[0] & 0xff)
44     #  define makedev(major, minor) { ((((unsigned int) (major)) << 8) \
45     				   | ((unsigned int) (minor))), 0 }
46     # endif
47     #endif
48     
49     #endif /* sys/sysmacros.h */
50