lfstack: Implement mutex-free stack head with transparent union (v2)

[urcu.git] / urcu / system.h

diff --git a/urcu/system.h b/urcu/system.h
index 38e8ecc771b345c1e463742a446b62f90cbad8d7..6f314595178e98385fd72e9d48c3f82de374081b 100644 (file)
--- a/urcu/system.h
+++ b/urcu/system.h
@@ -23,7 +23,8 @@
 #include <urcu/arch.h>
 
 /*
- * Identify a shared load. A cmm_smp_rmc() or cmm_smp_mc() should come before the load.
+ * Identify a shared load. A cmm_smp_rmc() or cmm_smp_mc() should come
+ * before the load.
  */
 #define _CMM_LOAD_SHARED(p)           CMM_ACCESS_ONCE(p)
 
@@ -37,19 +38,20 @@
        })
 
 /*
- * Identify a shared store. A cmm_smp_wmc() or cmm_smp_mc() should follow the store.
+ * Identify a shared store. A cmm_smp_wmc() or cmm_smp_mc() should
+ * follow the store.
  */
 #define _CMM_STORE_SHARED(x, v)        ({ CMM_ACCESS_ONCE(x) = (v); })
 
 /*
- * Store v into x, where x is located in shared memory. Performs the required
- * cache flush after writing. Returns v.
+ * Store v into x, where x is located in shared memory. Performs the
+ * required cache flush after writing. Returns v.
  */
-#define CMM_STORE_SHARED(x, v)         \
-       ({                              \
-               typeof(x) _v = _CMM_STORE_SHARED(x, v); \
-               cmm_smp_wmc();          \
-               _v;                     \
+#define CMM_STORE_SHARED(x, v)                                         \
+       ({                                                              \
+               __typeof__(x) _v = _CMM_STORE_SHARED(x, v);             \
+               cmm_smp_wmc();                                          \
+               _v = _v;        /* Work around clang "unused result" */ \
        })
 
 #endif /* _URCU_SYSTEM_H */