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

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright (c) 2018-2019 EfficiOS Inc. and Linux Foundation
 * Copyright (c) 2018-2019 Philippe Proulx <pproulx@efficios.com>
 */

#ifndef BABELTRACE_ASSERT_INTERNAL_H
#define BABELTRACE_ASSERT_INTERNAL_H

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

#include "common/macros.h"

BT_HIDDEN
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 */
Commit	Line	Data
464ebc31	1	/*
0235b0db MJ	2	* SPDX-License-Identifier: MIT
0235b0db MJ	3	*
98b15851 PP	4	* Copyright (c) 2018-2019 EfficiOS Inc. and Linux Foundation
98b15851 PP	5	* Copyright (c) 2018-2019 Philippe Proulx <pproulx@efficios.com>
464ebc31 PP	6	*/
464ebc31 PP	7
0235b0db MJ	8	#ifndef BABELTRACE_ASSERT_INTERNAL_H
	9	#define BABELTRACE_ASSERT_INTERNAL_H
	10
464ebc31	11	#include <assert.h>
91d81473 MJ	12	#include <glib.h>
	13
	14	#include "common/macros.h"
464ebc31	15
3b3873c8	16	BT_HIDDEN
4ee41178	17	extern void bt_common_assert_failed(const char *file, int line,
98b15851 PP	18	const char func, const char assertion)
98b15851 PP	19	__attribute__((noreturn));
4ee41178	20
464ebc31 PP	21	/*
464ebc31 PP	22	* Internal assertion (to detect logic errors on which the library user
98b15851	23	* has no influence). Use BT_ASSERT_PRE() or BT_ASSERT_POST() to check
1f9f5b4d PP	24	* preconditions or postconditions which must be directly or indirectly
1f9f5b4d PP	25	* satisfied by the library user.
98b15851 PP	26	*
98b15851 PP	27	* BT_ASSERT() is enabled in both debug and non-debug modes.
464ebc31	28	*/
4ee41178 SM	29	#define BT_ASSERT(_cond) \
	30	do { \
	31	if (!(_cond)) { \
	32	bt_common_assert_failed(__FILE__, __LINE__, __func__, \
91d81473	33	G_STRINGIFY(_cond)); \
4ee41178 SM	34	} \
4ee41178 SM	35	} while (0)
464ebc31 PP	36
	37	/*
	38	* Marks a function as being only used within a BT_ASSERT() context.
	39	*/
98b15851 PP	40	#define BT_ASSERT_FUNC
	41
	42	#ifdef BT_DEBUG_MODE
	43
	44	/*
	45	* Debug mode internal assertion.
	46	*/
	47	#define BT_ASSERT_DBG(_cond) BT_ASSERT(_cond)
	48
d7da1f66	49	/*
98b15851 PP	50	* Marks a function as being only used within a BT_ASSERT_DBG() context.
	51	*/
	52	#define BT_ASSERT_DBG_FUNC
	53
	54	#else /* BT_DEBUG_MODE */
	55
	56	/*
	57	* When `BT_DEBUG_MODE` is _not_ defined, define BT_ASSERT_DBG() macro
	58	* to the following to trick the compiler into thinking that the
	59	* variable passed as condition to the assertion is used. This is to
	60	* prevent set-but-not-used warnings from the compiler when assertions
	61	* are disabled. The sizeof() operator also makes sure that the `_cond`
	62	* expression is not evaluated, thus preventing unwanted side effects.
d7da1f66	63	*
98b15851 PP	64	* In-depth explanation:
98b15851 PP	65	* https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551
d7da1f66	66	*/
98b15851 PP	67	# define BT_ASSERT_DBG(_cond) ((void) sizeof((void) (_cond), 0))
	68	# define BT_ASSERT_DBG_FUNC __attribute__((unused))
	69
464ebc31 PP	70	#endif /* BT_DEBUG_MODE */
	71
	72	#endif /* BABELTRACE_ASSERT_INTERNAL_H */