1 files changed, 34 insertions, 0 deletions
diff --git a/src/libbasic/refcnt.h b/src/libbasic/refcnt.h
new file mode 100644
index 0000000000..1d77a6445a
--- /dev/null
+++ b/src/libbasic/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 })