From df40b0b99810121d9630730d6f58cf96bfea70e8 Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Mon, 18 Feb 2013 00:29:51 +0100
Subject: Use dirty read instead of union which can be unsafe on some platforms

---
 erts/emulator/beam/erl_thr_queue.h | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

(limited to 'erts/emulator/beam/erl_thr_queue.h')

diff --git a/erts/emulator/beam/erl_thr_queue.h b/erts/emulator/beam/erl_thr_queue.h
index edcf2c3823..ae8c7fb19a 100644
--- a/erts/emulator/beam/erl_thr_queue.h
+++ b/erts/emulator/beam/erl_thr_queue.h
@@ -76,13 +76,12 @@ typedef struct {
 typedef struct ErtsThrQElement_t_ ErtsThrQElement_t;
 typedef struct ErtsThrQElement_t ErtsThrQPrepEnQ_t;
 
-typedef union {
-    erts_atomic_t atmc;
-    ErtsThrQElement_t *ptr;
-} ErtsThrQPtr_t;
-
 struct ErtsThrQElement_t_ {
-    ErtsThrQPtr_t next;
+#ifdef USE_THREADS
+    erts_atomic_t next;
+#else
+    ErtsThrQElement_t *next;
+#endif
     union {
 	erts_atomic_t atmc;
 	void *ptr;
@@ -130,7 +129,7 @@ struct ErtsThrQ_t_ {
      * thread dequeuing.
      */
     struct {
-	ErtsThrQPtr_t head;
+	erts_atomic_t head;
 	ErtsThrQLive_t live;
 	ErtsThrQElement_t *first;
 	ErtsThrQElement_t *unref_end;
-- 
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