HCoop / bpt / guile.git / blame
| Commit | Line | Data |
|---|---|---|
| 8912421c | 1 | /* Determine alignment of types. |
| 5e69ceb7 | 2 | Copyright (C) 2003-2004, 2006, 2009-2014 Free Software Foundation, Inc. |
| 8912421c LC |
3 | |
| 4 | This program is free software; you can redistribute it and/or modify | |
| 5 | it under the terms of the GNU Lesser General Public License as published by | |
| 6 | the Free Software Foundation; either version 2, or (at your option) | |
| 7 | any later version. | |
| 8 | ||
| 9 | This program is distributed in the hope that it will be useful, | |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 12 | GNU Lesser General Public License for more details. | |
| 13 | ||
| 14 | You should have received a copy of the GNU Lesser General Public License | |
| 005de2e8 | 15 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
| 8912421c LC |
16 | |
| 17 | #ifndef _ALIGNOF_H | |
| 18 | #define _ALIGNOF_H | |
| 19 | ||
| 20 | #include <stddef.h> | |
| 21 | ||
| 7f1ea859 LC |
22 | /* alignof_slot (TYPE) |
| 23 | Determine the alignment of a structure slot (field) of a given type, | |
| 8912421c | 24 | at compile time. Note that the result depends on the ABI. |
| 7f1ea859 LC |
25 | This is the same as alignof (TYPE) and _Alignof (TYPE), defined in |
| 26 | <stdalign.h> if __alignof_is_defined is 1. | |
| 8912421c LC |
27 | Note: The result cannot be used as a value for an 'enum' constant, |
| 28 | due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc. */ | |
| 29 | #if defined __cplusplus | |
| 30 | template <class type> struct alignof_helper { char __slot1; type __slot2; }; | |
| 31 | # define alignof_slot(type) offsetof (alignof_helper<type>, __slot2) | |
| 32 | #else | |
| 33 | # define alignof_slot(type) offsetof (struct { char __slot1; type __slot2; }, __slot2) | |
| 34 | #endif | |
| 35 | ||
| 7f1ea859 LC |
36 | /* alignof_type (TYPE) |
| 37 | Determine the good alignment of an object of the given type at compile time. | |
| 8912421c LC |
38 | Note that this is not necessarily the same as alignof_slot(type). |
| 39 | For example, with GNU C on x86 platforms: alignof_type(double) = 8, but | |
| 40 | - when -malign-double is not specified: alignof_slot(double) = 4, | |
| 41 | - when -malign-double is specified: alignof_slot(double) = 8. | |
| 42 | Note: The result cannot be used as a value for an 'enum' constant, | |
| 43 | due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc. */ | |
| 5e69ceb7 | 44 | #if defined __GNUC__ || defined __IBM__ALIGNOF__ |
| 8912421c LC |
45 | # define alignof_type __alignof__ |
| 46 | #else | |
| 47 | # define alignof_type alignof_slot | |
| 48 | #endif | |
| 49 | ||
| 8912421c | 50 | #endif /* _ALIGNOF_H */ |