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Diffstat (limited to 'src/libsystemd-basic/include/systemd-basic/refcnt.h')
| -rw-r--r-- | src/libsystemd-basic/include/systemd-basic/refcnt.h | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/libsystemd-basic/include/systemd-basic/refcnt.h b/src/libsystemd-basic/include/systemd-basic/refcnt.h new file mode 100644 index 0000000000..1d77a6445a --- /dev/null +++ b/src/libsystemd-basic/include/systemd-basic/refcnt.h @@ -0,0 +1,34 @@ +#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 }) |