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

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#ifndef _BABELTRACE_INTERNAL_H
#define _BABELTRACE_INTERNAL_H

#ifdef __cplusplus
extern "C" {
#endif

#ifdef __cplusplus
#define BT_EXTERN_C extern "C"
#else
#define BT_EXTERN_C
#endif

#define bt_max_t(type, a, b)	\
	((type) (a) > (type) (b) ? (type) (a) : (type) (b))

/*
 * BT_EXPORT: set the visibility for exported functions.
 */
#if defined(_WIN32) || defined(__CYGWIN__)
#define BT_EXPORT
#else
#define BT_EXPORT __attribute__((visibility("default")))
#endif

/*
 * BT_NOEXCEPT: defined to `noexcept` if compiling as C++, else empty.
 */
#if defined(__cplusplus)
#define BT_NOEXCEPT noexcept
#else
#define BT_NOEXCEPT
#endif

/* Enable `txt` if developer mode is enabled. */
#ifdef BT_DEV_MODE
#define BT_IF_DEV_MODE(txt) txt
#else
#define BT_IF_DEV_MODE(txt)
#endif

/* Wrapper for g_array_index that adds bound checking.  */
#define bt_g_array_index(a, t, i)		\
	g_array_index((a), t, ({ BT_ASSERT_DBG((i) < (a)->len); (i); }))

/*
 * Copied from:
 * <https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551>:
 *
 * * sizeof() ensures that the expression is not evaluated at all, so
 *   its side-effects don't happen. That is to be consistent with the
 *   usual behaviour of debug-only constructs, such as assert().
 *
 * * `((_expr), 0)` uses the comma operator to swallow the actual type
 *   of `(_expr)`. This is to prevent VLAs from triggering evaluation.
 *
 * * `(void)` explicitly ignores the result of `(_expr)` and sizeof() so
 *   no "unused value" warning appears.
 */

#define BT_USE_EXPR(_expr)		((void) sizeof((void) (_expr), 0))
#define BT_USE_EXPR2(_expr1, _expr2)					\
	((void) sizeof((void) (_expr1), (void) (_expr2), 0))
#define BT_USE_EXPR3(_expr1, _expr2, _expr3)				\
	((void) sizeof((void) (_expr1), (void) (_expr2), (void) (_expr3), 0))
#define BT_USE_EXPR4(_expr1, _expr2, _expr3, _expr4)			\
	((void) sizeof((void) (_expr1), (void) (_expr2),		\
		(void) (_expr3), (void) (_expr4), 0))
#define BT_USE_EXPR5(_expr1, _expr2, _expr3, _expr4, _expr5)		\
	((void) sizeof((void) (_expr1), (void) (_expr2),		\
		(void) (_expr3), (void) (_expr4), (void) (_expr5), 0))

#define BT_DIAG_PUSH _Pragma ("GCC diagnostic push")
#define BT_DIAG_POP _Pragma ("GCC diagnostic push")

#define BT_DIAG_IGNORE_SHADOW _Pragma("GCC diagnostic ignored \"-Wshadow\"")

#if defined __clang__
#  if __has_warning("-Wunused-but-set-variable")
#    define BT_DIAG_IGNORE_UNUSED_BUT_SET_VARIABLE \
	_Pragma("GCC diagnostic ignored \"-Wunused-but-set-variable\"")
#  endif
#endif

#if !defined BT_DIAG_IGNORE_UNUSED_BUT_SET_VARIABLE
#  define BT_DIAG_IGNORE_UNUSED_BUT_SET_VARIABLE
#endif

#ifdef __cplusplus
}
#endif

#endif
Commit	Line	Data
	1	/*
	2	* SPDX-License-Identifier: MIT
	3	*
	4	* Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*/
	6
	7	#ifndef _BABELTRACE_INTERNAL_H
	8	#define _BABELTRACE_INTERNAL_H
	9
	10	#ifdef __cplusplus
	11	extern "C" {
	12	#endif
	13
	14	#ifdef __cplusplus
	15	#define BT_EXTERN_C extern "C"
	16	#else
	17	#define BT_EXTERN_C
	18	#endif
	19
	20	#define bt_max_t(type, a, b) \
	21	((type) (a) > (type) (b) ? (type) (a) : (type) (b))
	22
	23	/*
	24	* BT_EXPORT: set the visibility for exported functions.
	25	*/
	26	#if defined(_WIN32) \|\| defined(__CYGWIN__)
	27	#define BT_EXPORT
	28	#else
	29	#define BT_EXPORT __attribute__((visibility("default")))
	30	#endif
	31
	32	/*
	33	* BT_NOEXCEPT: defined to `noexcept` if compiling as C++, else empty.
	34	*/
	35	#if defined(__cplusplus)
	36	#define BT_NOEXCEPT noexcept
	37	#else
	38	#define BT_NOEXCEPT
	39	#endif
	40
	41	/* Enable `txt` if developer mode is enabled. */
	42	#ifdef BT_DEV_MODE
	43	#define BT_IF_DEV_MODE(txt) txt
	44	#else
	45	#define BT_IF_DEV_MODE(txt)
	46	#endif
	47
	48	/* Wrapper for g_array_index that adds bound checking. */
	49	#define bt_g_array_index(a, t, i) \
	50	g_array_index((a), t, ({ BT_ASSERT_DBG((i) < (a)->len); (i); }))
	51
	52	/*
	53	* Copied from:
	54	* <https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551>:
	55	*
	56	* * sizeof() ensures that the expression is not evaluated at all, so
	57	* its side-effects don't happen. That is to be consistent with the
	58	* usual behaviour of debug-only constructs, such as assert().
	59	*
	60	* * `((_expr), 0)` uses the comma operator to swallow the actual type
	61	* of `(_expr)`. This is to prevent VLAs from triggering evaluation.
	62	*
	63	* * `(void)` explicitly ignores the result of `(_expr)` and sizeof() so
	64	* no "unused value" warning appears.
	65	*/
	66
	67	#define BT_USE_EXPR(_expr) ((void) sizeof((void) (_expr), 0))
	68	#define BT_USE_EXPR2(_expr1, _expr2) \
	69	((void) sizeof((void) (_expr1), (void) (_expr2), 0))
	70	#define BT_USE_EXPR3(_expr1, _expr2, _expr3) \
	71	((void) sizeof((void) (_expr1), (void) (_expr2), (void) (_expr3), 0))
	72	#define BT_USE_EXPR4(_expr1, _expr2, _expr3, _expr4) \
	73	((void) sizeof((void) (_expr1), (void) (_expr2), \
	74	(void) (_expr3), (void) (_expr4), 0))
	75	#define BT_USE_EXPR5(_expr1, _expr2, _expr3, _expr4, _expr5) \
	76	((void) sizeof((void) (_expr1), (void) (_expr2), \
	77	(void) (_expr3), (void) (_expr4), (void) (_expr5), 0))
	78
	79	#define BT_DIAG_PUSH _Pragma ("GCC diagnostic push")
	80	#define BT_DIAG_POP _Pragma ("GCC diagnostic push")
	81
	82	#define BT_DIAG_IGNORE_SHADOW _Pragma("GCC diagnostic ignored \"-Wshadow\"")
	83
	84	#if defined __clang__
	85	# if __has_warning("-Wunused-but-set-variable")
	86	# define BT_DIAG_IGNORE_UNUSED_BUT_SET_VARIABLE \
	87	_Pragma("GCC diagnostic ignored \"-Wunused-but-set-variable\"")
	88	# endif
	89	#endif
	90
	91	#if !defined BT_DIAG_IGNORE_UNUSED_BUT_SET_VARIABLE
	92	# define BT_DIAG_IGNORE_UNUSED_BUT_SET_VARIABLE
	93	#endif
	94
	95	#ifdef __cplusplus
	96	}
	97	#endif
	98
	99	#endif