src/common/assert.h

   1 #ifndef BABELTRACE_ASSERT_INTERNAL_H
   2 #define BABELTRACE_ASSERT_INTERNAL_H
   3
   4 /*
   5  * Copyright (c) 2018 EfficiOS Inc. and Linux Foundation
   6  * Copyright (c) 2018 Philippe Proulx <pproulx@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE.
  25  */
  26
  27 #include <assert.h>
  28 #include <glib.h>
  29
  30 #include "common/macros.h"
  31
  32 #ifdef BT_DEBUG_MODE
  33
  34 extern void bt_common_assert_failed(const char *file, int line,
  35         const char *func, const char *assertion) __attribute__((noreturn));
  36
  37 /*
  38  * Internal assertion (to detect logic errors on which the library user
  39  * has no influence). Use BT_ASSERT_PRE() or BT_ASSERT_POST() to check
  40  * preconditions or postconditions which must be directly or indirectly
  41  * satisfied by the library user.
  42  */
  43 #define BT_ASSERT(_cond)                                                       \
  44         do {                                                                   \
  45                 if (!(_cond)) {                                                \
  46                         bt_common_assert_failed(__FILE__, __LINE__, __func__,  \
  47                                 G_STRINGIFY(_cond));                           \
  48                 }                                                              \
  49         } while (0)
  50
  51 /*
  52  * Marks a function as being only used within a BT_ASSERT() context.
  53  */
  54 # define BT_ASSERT_FUNC
  55 #else
  56 /*
  57  * When BT_DEBUG_MODE is not defined, define BT_ASSERT() macro to the following
  58  * to trick the compiler into thinking that the variable passed as condition to
  59  * the assertion is used. This is to prevent set-but-not-used warnings from the
  60  * compiler when assertions are disabled. The `sizeof` operator also makes sure
  61  * that the `_cond` expression is not evaluated, thus preventing unwanted side
  62  * effects.
  63  *
  64  * In-depth explanation: https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551
  65  */
  66 # define BT_ASSERT(_cond)       ((void) sizeof((void) (_cond), 0))
  67 # define BT_ASSERT_FUNC         __attribute__((unused))
  68 #endif /* BT_DEBUG_MODE */
  69
  70 #endif /* BABELTRACE_ASSERT_INTERNAL_H */