| /* Determine alignment of types. |
| Copyright (C) 2003-2004, 2006, 2009-2017 Free Software Foundation, Inc. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| This program 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 General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
| |
| #ifndef _ALIGNOF_H |
| #define _ALIGNOF_H |
| |
| #include <stddef.h> |
| |
| /* alignof_slot (TYPE) |
| Determine the alignment of a structure slot (field) of a given type, |
| at compile time. Note that the result depends on the ABI. |
| This is the same as alignof (TYPE) and _Alignof (TYPE), defined in |
| <stdalign.h> if __alignof_is_defined is 1. |
| Note: The result cannot be used as a value for an 'enum' constant, |
| due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc. */ |
| #if defined __cplusplus |
| template <class type> struct alignof_helper { char __slot1; type __slot2; }; |
| # define alignof_slot(type) offsetof (alignof_helper<type>, __slot2) |
| #else |
| # define alignof_slot(type) offsetof (struct { char __slot1; type __slot2; }, __slot2) |
| #endif |
| |
| /* alignof_type (TYPE) |
| Determine the good alignment of an object of the given type at compile time. |
| Note that this is not necessarily the same as alignof_slot(type). |
| For example, with GNU C on x86 platforms: alignof_type(double) = 8, but |
| - when -malign-double is not specified: alignof_slot(double) = 4, |
| - when -malign-double is specified: alignof_slot(double) = 8. |
| Note: The result cannot be used as a value for an 'enum' constant, |
| due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc. */ |
| #if defined __GNUC__ || defined __IBM__ALIGNOF__ |
| # define alignof_type __alignof__ |
| #else |
| # define alignof_type alignof_slot |
| #endif |
| |
| #endif /* _ALIGNOF_H */ |