diff options
Diffstat (limited to 'bits')
| -rw-r--r-- | bits/sysmacros.h | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/bits/sysmacros.h b/bits/sysmacros.h new file mode 100644 index 0000000000..e2c0bc2f65 --- /dev/null +++ b/bits/sysmacros.h @@ -0,0 +1,74 @@ +/* Definitions of macros to access `dev_t' values. + Copyright (C) 1996-2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _BITS_SYSMACROS_H +#define _BITS_SYSMACROS_H 1 + +#ifndef _SYS_SYSMACROS_H +# error "Never include <bits/sysmacros.h> directly; use <sys/sysmacros.h> instead." +#endif + +/* dev_t in glibc is a 64-bit quantity, with 32-bit major and minor numbers. + Our default encoding is MMMM Mmmm mmmM MMmm, where M is a hex digit of + the major number and m is a hex digit of the minor number. This is + downward compatible with legacy systems where dev_t is 16 bits wide, + encoded as MMmm. It is also downward compatible with the Linux kernel, + which (as of 2016) uses 32-bit dev_t, encoded as mmmM MMmm. + + Systems that use an incompatible encoding for dev_t should override this + file in the appropriate sysdeps subdirectory. */ + +#define __SYSMACROS_DECLARE_MAJOR(DECL_TEMPL) \ + DECL_TEMPL(unsigned int, major, (__dev_t __dev)) + +#define __SYSMACROS_DEFINE_MAJOR(DECL_TEMPL) \ + __SYSMACROS_DECLARE_MAJOR (DECL_TEMPL) \ + { \ + unsigned int __major; \ + __major = ((__dev & (__dev_t) 0x00000000000fff00u) >> 8); \ + __major |= ((__dev & (__dev_t) 0xfffff00000000000u) >> 32); \ + return __major; \ + } + +#define __SYSMACROS_DECLARE_MINOR(DECL_TEMPL) \ + DECL_TEMPL(unsigned int, minor, (__dev_t __dev)) + +#define __SYSMACROS_DEFINE_MINOR(DECL_TEMPL) \ + __SYSMACROS_DECLARE_MINOR (DECL_TEMPL) \ + { \ + unsigned int __minor; \ + __minor = ((__dev & (__dev_t) 0x00000000000000ffu) >> 0); \ + __minor |= ((__dev & (__dev_t) 0x00000ffffff00000u) >> 12); \ + return __minor; \ + } + +#define __SYSMACROS_DECLARE_MAKEDEV(DECL_TEMPL) \ + DECL_TEMPL(__dev_t, makedev, (unsigned int __major, unsigned int __minor)) + +#define __SYSMACROS_DEFINE_MAKEDEV(DECL_TEMPL) \ + __SYSMACROS_DECLARE_MAKEDEV (DECL_TEMPL) \ + { \ + __dev_t __dev; \ + __dev = (((__dev_t) (__major & 0x00000fffu)) << 8); \ + __dev |= (((__dev_t) (__major & 0xfffff000u)) << 32); \ + __dev |= (((__dev_t) (__minor & 0x000000ffu)) << 0); \ + __dev |= (((__dev_t) (__minor & 0xffffff00u)) << 12); \ + return __dev; \ + } + +#endif /* bits/sysmacros.h */ |