include/babeltrace/assert-internal.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 <babeltrace/babeltrace-internal.h>
  29
  30 #ifdef BT_DEBUG_MODE
  31 /*
  32  * Internal assertion (to detect logic errors on which the library user
  33  * has no influence). Use BT_ASSERT_PRE() to check a precondition which
  34  * must be directly or indirectly satisfied by the library user.
  35  */
  36 # define BT_ASSERT(_cond)       do { assert(_cond); } while (0)
  37
  38 /*
  39  * Marks a function as being only used within a BT_ASSERT() context.
  40  */
  41 # define BT_ASSERT_FUNC
  42 #else
  43 /*
  44  * When BT_DEBUG_MODE is not defined, define BT_ASSERT() macro to the following
  45  * to trick the compiler into thinking that the variable passed as condition to
  46  * the assertion is used. This is to prevent set-but-not-used warnings from the
  47  * compiler when assertions are disabled. The `sizeof` operator also makes sure
  48  * that the `_cond` expression is not evaluated, thus preventing unwanted side
  49  * effects.
  50  *
  51  * In-depth explanation: https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551
  52  */
  53 # define BT_ASSERT(_cond)       ((void) sizeof((void) (_cond), 0))
  54 # define BT_ASSERT_FUNC         BT_UNUSED
  55 #endif /* BT_DEBUG_MODE */
  56
  57 #endif /* BABELTRACE_ASSERT_INTERNAL_H */