Always evaluate BT_ASSERT(); add BT_ASSERT_DBG() for debug mode only

[babeltrace.git] / src / common / assert.h

#ifndef BABELTRACE_ASSERT_INTERNAL_H
#define BABELTRACE_ASSERT_INTERNAL_H

/*
 * Copyright (c) 2018-2019 EfficiOS Inc. and Linux Foundation
 * Copyright (c) 2018-2019 Philippe Proulx <pproulx@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <assert.h>
#include <glib.h>

#include "common/macros.h"

extern void bt_common_assert_failed(const char *file, int line,
		const char *func, const char *assertion)
		__attribute__((noreturn));

/*
 * Internal assertion (to detect logic errors on which the library user
 * has no influence). Use BT_ASSERT_PRE*() or BT_ASSERT_POST*() to check
 * preconditions or postconditions which must be directly or indirectly
 * satisfied by the library user.
 *
 * BT_ASSERT() is enabled in both debug and non-debug modes.
 */
#define BT_ASSERT(_cond)                                                       \
	do {                                                                   \
		if (!(_cond)) {                                                \
			bt_common_assert_failed(__FILE__, __LINE__, __func__,  \
				G_STRINGIFY(_cond));                           \
		}                                                              \
	} while (0)

/*
 * Marks a function as being only used within a BT_ASSERT() context.
 */
#define BT_ASSERT_FUNC

#ifdef BT_DEBUG_MODE

/*
 * Debug mode internal assertion.
 */
#define BT_ASSERT_DBG(_cond)	BT_ASSERT(_cond)

/*
 * Marks a function as being only used within a BT_ASSERT_DBG() context.
 */
#define BT_ASSERT_DBG_FUNC

#else /* BT_DEBUG_MODE */

/*
 * When `BT_DEBUG_MODE` is _not_ defined, define BT_ASSERT_DBG() macro
 * to the following to trick the compiler into thinking that the
 * variable passed as condition to the assertion is used. This is to
 * prevent set-but-not-used warnings from the compiler when assertions
 * are disabled. The sizeof() operator also makes sure that the `_cond`
 * expression is not evaluated, thus preventing unwanted side effects.
 *
 * In-depth explanation:
 * https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551
 */
# define BT_ASSERT_DBG(_cond)	((void) sizeof((void) (_cond), 0))
# define BT_ASSERT_DBG_FUNC	__attribute__((unused))

#endif /* BT_DEBUG_MODE */

#endif /* BABELTRACE_ASSERT_INTERNAL_H */