| 1 | /* |
| 2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> |
| 3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License, version 2 only, |
| 7 | * as published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 12 | * more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License along |
| 15 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 17 | */ |
| 18 | |
| 19 | #ifndef _MACROS_H |
| 20 | #define _MACROS_H |
| 21 | |
| 22 | #include <stdlib.h> |
| 23 | |
| 24 | /* |
| 25 | * Takes a pointer x and transform it so we can use it to access members |
| 26 | * without a function call. Here an example: |
| 27 | * |
| 28 | * #define GET_SIZE(x) LTTNG_REF(x)->size |
| 29 | * |
| 30 | * struct { int size; } s; |
| 31 | * |
| 32 | * printf("size : %d\n", GET_SIZE(&s)); |
| 33 | * |
| 34 | * For this example we can't use something like this for compatibility purpose |
| 35 | * since this will fail: |
| 36 | * |
| 37 | * #define GET_SIZE(x) x->size; |
| 38 | * |
| 39 | * This is mostly use for the compatibility layer of lttng-tools. See |
| 40 | * poll/epoll for a good example. Since x can be on the stack or allocated |
| 41 | * memory using malloc(), we must use generic accessors for compat in order to |
| 42 | * *not* use a function to access members and not the variable name. |
| 43 | */ |
| 44 | #define LTTNG_REF(x) ((typeof(*x) *)(x)) |
| 45 | |
| 46 | /* |
| 47 | * Memory allocation zeroed |
| 48 | */ |
| 49 | #define zmalloc(x) calloc(1, x) |
| 50 | |
| 51 | #ifndef ARRAY_SIZE |
| 52 | #define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0]))) |
| 53 | #endif |
| 54 | |
| 55 | #endif /* _MACROS_H */ |