include/babeltrace/compiler-internal.h

   1 #ifndef _BABELTRACE_COMPILER_H
   2 #define _BABELTRACE_COMPILER_H
   3
   4 /*
   5  * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  */
  25
  26 #include <stddef.h>     /* for offsetof */
  27
  28 #define MAYBE_BUILD_BUG_ON(cond) ((void)sizeof(char[1 - 2 * !!(cond)]))
  29
  30 #ifndef container_of
  31 #define container_of(ptr, type, member)                                 \
  32         ({                                                              \
  33                 const typeof(((type *)NULL)->member) * __ptr = (ptr);   \
  34                 (type *)((char *)__ptr - offsetof(type, member));       \
  35         })
  36 #endif
  37
  38 #define BT_ARRAY_SIZE(arr)      (sizeof(arr) / sizeof((arr)[0]))
  39
  40 #endif /* _BABELTRACE_COMPILER_H */