[thirdparty/systemd.git] / src / basic / refcnt.h

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

#pragma once

/***
  This file is part of systemd.

  Copyright 2013 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

/* A type-safe atomic refcounter.
 *
 * DO NOT USE THIS UNLESS YOU ACTUALLY CARE ABOUT THREAD SAFETY! */

typedef struct {
        volatile unsigned _value;
} RefCount;

#define REFCNT_GET(r) ((r)._value)
#define REFCNT_INC(r) (__sync_add_and_fetch(&(r)._value, 1))
#define REFCNT_DEC(r) (__sync_sub_and_fetch(&(r)._value, 1))

#define REFCNT_INIT ((RefCount) { ._value = 1 })
Commit	Line	Data
e4ee6e5c LP	1	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/
	2
	3	#pragma once
	4
	5	/***
	6	This file is part of systemd.
	7
	8	Copyright 2013 Lennart Poettering
	9
	10	systemd is free software; you can redistribute it and/or modify it
	11	under the terms of the GNU Lesser General Public License as published by
	12	the Free Software Foundation; either version 2.1 of the License, or
	13	(at your option) any later version.
	14
	15	systemd is distributed in the hope that it will be useful, but
	16	WITHOUT ANY WARRANTY; without even the implied warranty of
	17	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	18	Lesser General Public License for more details.
	19
	20	You should have received a copy of the GNU Lesser General Public License
	21	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	22	***/
	23
57de20dd LP	24	/* A type-safe atomic refcounter.
	25	*
	26	* DO NOT USE THIS UNLESS YOU ACTUALLY CARE ABOUT THREAD SAFETY! */
e4ee6e5c LP	27
	28	typedef struct {
	29	volatile unsigned _value;
	30	} RefCount;
	31
	32	#define REFCNT_GET(r) ((r)._value)
	33	#define REFCNT_INC(r) (__sync_add_and_fetch(&(r)._value, 1))
	34	#define REFCNT_DEC(r) (__sync_sub_and_fetch(&(r)._value, 1))
	35
	36	#define REFCNT_INIT ((RefCount) { ._value = 1 })