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

   1 /* Definitions of macros to access `dev_t' values.
   2    Copyright (C) 1996, 1997, 1999, 2003, 2004, 2007, 2011
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  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 __BEGIN_DECLS
  30
  31 __extension__
  32 extern unsigned int gnu_dev_major (unsigned long long int __dev)
  33      __THROW __attribute_const__;
  34 __extension__
  35 extern unsigned int gnu_dev_minor (unsigned long long int __dev)
  36      __THROW __attribute_const__;
  37 __extension__
  38 extern unsigned long long int gnu_dev_makedev (unsigned int __major,
  39                                                unsigned int __minor)
  40      __THROW __attribute_const__;
  41
  42 # if defined __GNUC__ && __GNUC__ >= 2 && defined __USE_EXTERN_INLINES
  43 __extension__ __extern_inline __attribute_const__ unsigned int
  44 __NTH (gnu_dev_major (unsigned long long int __dev))
  45 {
  46   return ((__dev >> 8) & 0xfff) | ((unsigned int) (__dev >> 32) & ~0xfff);
  47 }
  48
  49 __extension__ __extern_inline __attribute_const__ unsigned int
  50 __NTH (gnu_dev_minor (unsigned long long int __dev))
  51 {
  52   return (__dev & 0xff) | ((unsigned int) (__dev >> 12) & ~0xff);
  53 }
  54
  55 __extension__ __extern_inline __attribute_const__ unsigned long long int
  56 __NTH (gnu_dev_makedev (unsigned int __major, unsigned int __minor))
  57 {
  58   return ((__minor & 0xff) | ((__major & 0xfff) << 8)
  59           | (((unsigned long long int) (__minor & ~0xff)) << 12)
  60           | (((unsigned long long int) (__major & ~0xfff)) << 32));
  61 }
  62 # endif
  63 __END_DECLS
  64
  65 /* Access the functions with their traditional names.  */
  66 # define major(dev) gnu_dev_major (dev)
  67 # define minor(dev) gnu_dev_minor (dev)
  68 # define makedev(maj, min) gnu_dev_makedev (maj, min)
  69 #endif
  70
  71 #endif /* sys/sysmacros.h */