[lttng-tools.git] / src / common / macros.h

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _MACROS_H
#define _MACROS_H

#include <stdlib.h>

/*
 * Takes a pointer x and transform it so we can use it to access members
 * without a function call. Here an example:
 *
 *    #define GET_SIZE(x) LTTNG_REF(x)->size
 *
 *    struct { int size; } s;
 *
 *    printf("size : %d\n", GET_SIZE(&s));
 *
 * For this example we can't use something like this for compatibility purpose
 * since this will fail:
 *
 *    #define GET_SIZE(x) x->size;
 *
 * This is mostly use for the compatibility layer of lttng-tools. See
 * poll/epoll for a good example. Since x can be on the stack or allocated
 * memory using malloc(), we must use generic accessors for compat in order to
 * *not* use a function to access members and not the variable name.
 */
#define LTTNG_REF(x) ((typeof(*x) *)(x))

/*
 * Memory allocation zeroed
 */
static inline
void *zmalloc(size_t len)
{
	return calloc(1, len);
}

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
#endif

#ifndef max
#define max(a, b) ((a) > (b) ? (a) : (b))
#endif

#ifndef max_t
#define max_t(type, a, b)	((type) max(a, b))
#endif

#ifndef min
#define min(a, b) ((a) < (b) ? (a) : (b))
#endif

#ifndef LTTNG_PACKED
#define LTTNG_PACKED __attribute__((__packed__))
#endif

#ifndef LTTNG_HIDDEN
#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
#endif

#endif /* _MACROS_H */
Commit	Line	Data
990570ed DG	1	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
d14d33bf AM	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License, version 2 only,
	7	* as published by the Free Software Foundation.
990570ed DG	8	*
	9	* This program is distributed in the hope that it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
d14d33bf	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
990570ed DG	12	* more details.
990570ed DG	13	*
d14d33bf AM	14	* You should have received a copy of the GNU General Public License along
	15	* with this program; if not, write to the Free Software Foundation, Inc.,
	16	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
990570ed DG	17	*/
	18
	19	#ifndef _MACROS_H
	20	#define _MACROS_H
	21
	22	#include <stdlib.h>
	23
	24	/*
	25	* Takes a pointer x and transform it so we can use it to access members
	26	* without a function call. Here an example:
	27	*
	28	* #define GET_SIZE(x) LTTNG_REF(x)->size
	29	*
	30	* struct { int size; } s;
	31	*
	32	* printf("size : %d\n", GET_SIZE(&s));
	33	*
	34	* For this example we can't use something like this for compatibility purpose
	35	* since this will fail:
	36	*
	37	* #define GET_SIZE(x) x->size;
	38	*
	39	* This is mostly use for the compatibility layer of lttng-tools. See
	40	* poll/epoll for a good example. Since x can be on the stack or allocated
	41	* memory using malloc(), we must use generic accessors for compat in order to
	42	* not use a function to access members and not the variable name.
	43	*/
	44	#define LTTNG_REF(x) ((typeof(x) )(x))
	45
	46	/*
	47	* Memory allocation zeroed
	48	*/
4616a46c MD	49	static inline
	50	void *zmalloc(size_t len)
	51	{
	52	return calloc(1, len);
	53	}
990570ed DG	54
	55	#ifndef ARRAY_SIZE
	56	#define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0])))
	57	#endif
	58
cf3f19ae SM	59	#ifndef max
	60	#define max(a, b) ((a) > (b) ? (a) : (b))
	61	#endif
	62
331744e3 JD	63	#ifndef max_t
	64	#define max_t(type, a, b) ((type) max(a, b))
	65	#endif
	66
cf3f19ae SM	67	#ifndef min
	68	#define min(a, b) ((a) < (b) ? (a) : (b))
	69	#endif
	70
54c90d10 DG	71	#ifndef LTTNG_PACKED
	72	#define LTTNG_PACKED __attribute__((__packed__))
	73	#endif
	74
99c815c1 DG	75	#ifndef LTTNG_HIDDEN
	76	#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
	77	#endif
	78
990570ed	79	#endif /* _MACROS_H */