sysdeps/unix/sysv/linux/sys/sysmacros.h

   1 /* Definitions of macros to access `dev_t' values.
   2    Copyright (C) 1996, 1997, 1999, 2003 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _SYS_SYSMACROS_H
  21 #define _SYS_SYSMACROS_H        1
  22
  23 #include <features.h>
  24
  25 /* If the compiler does not know long long it is out of luck.  We are
  26    not going to hack weird hacks to support the dev_t representation
  27    they need.  */
  28 #ifdef __GLIBC_HAVE_LONG_LONG
  29 extern unsigned int inline major (unsigned long long int __dev) __THROW;
  30 extern unsigned int inline minor (unsigned long long int __dev) __THROW;
  31 extern unsigned long long int inline makedev (unsigned int __major,
  32                                               unsigned int __minor) __THROW;
  33
  34 # if defined __GNUC__ && __GNUC__ >= 2
  35 extern inline unsigned int
  36 major (unsigned long long int __dev)
  37 {
  38   return ((__dev >> 8) & 0xfff) | ((unsigned int) (__dev >> 32) & ~0xfff);
  39 }
  40
  41 extern inline unsigned int
  42 minor (unsigned long long int __dev)
  43 {
  44   return (__dev & 0xff) | ((unsigned int) (__dev >> 12) & ~0xff);
  45 }
  46
  47 extern inline unsigned long long int
  48 makedev (unsigned int __major, unsigned int __minor)
  49 {
  50   return ((__minor & 0xff) | ((__major & 0xfff) << 8)
  51           | (((unsigned long long int) (__minor & ~0xff)) << 12)
  52           | (((unsigned long long int) (__major & ~0xfff)) << 32));
  53 }
  54 # endif
  55
  56
  57 /* Historically the three symbols were macros.  In case some programs
  58    use #ifdef to check for definition provide some dummy macros.  */
  59 # define major(dev) major (dev)
  60 # define minor(dev) minor (dev)
  61 # define makedev(maj, min) makedev (maj, min)
  62 #endif
  63
  64 #endif /* sys/sysmacros.h */