[ovs-dev] [PATCH 2/3] clang: Fix the "expression result unused" warning.

[Alex Wang]

This commit makes macro function "ASSIGN_CONTAINER()" evaluates
to "(void)0". This is to avoid the 'clang' warning: "expression
result unused", since most of time, the final evaluated value
is not used.

Signed-off-by: Alex Wang <alexw at nicira.com>
---
 lib/classifier.h |    2 +-
 lib/hindex.h     |    2 +-
 lib/hmap.h       |    2 +-
 lib/list.h       |   10 +++++-----
 lib/util.h       |    4 ++--
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/classifier.h b/lib/classifier.h
index 09b3a13..a14a24d 100644
--- a/lib/classifier.h
+++ b/lib/classifier.h
@@ -132,7 +132,7 @@ struct cls_rule *cls_cursor_next(struct cls_cursor *, struct cls_rule *);
     for (ASSIGN_CONTAINER(RULE, cls_cursor_first(CURSOR), MEMBER);      \
          (RULE != OBJECT_CONTAINING(NULL, RULE, MEMBER)                 \
           ? ASSIGN_CONTAINER(NEXT, cls_cursor_next(CURSOR, &(RULE)->MEMBER), \
-                             MEMBER)                                    \
+                             MEMBER), 1                                 \
           : 0);                                                         \
          (RULE) = (NEXT))
 
diff --git a/lib/hindex.h b/lib/hindex.h
index ce46596..fb6b6d2 100644
--- a/lib/hindex.h
+++ b/lib/hindex.h
@@ -147,7 +147,7 @@ struct hindex_node *hindex_node_with_hash(const struct hindex *, size_t hash);
 #define HINDEX_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HINDEX)                \
     for (ASSIGN_CONTAINER(NODE, hindex_first(HINDEX), MEMBER);          \
          (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)                 \
-          ? ASSIGN_CONTAINER(NEXT, hindex_next(HINDEX, &(NODE)->MEMBER), MEMBER) \
+          ? ASSIGN_CONTAINER(NEXT, hindex_next(HINDEX, &(NODE)->MEMBER), MEMBER), 1 \
           : 0);                                                         \
          (NODE) = (NEXT))
 
diff --git a/lib/hmap.h b/lib/hmap.h
index c7df62a..ab7d3ae 100644
--- a/lib/hmap.h
+++ b/lib/hmap.h
@@ -146,7 +146,7 @@ bool hmap_contains(const struct hmap *, const struct hmap_node *);
 #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP)                    \
     for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER);              \
          (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)                  \
-          ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER) \
+          ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \
           : 0);                                                         \
          (NODE) = (NEXT))
 
diff --git a/lib/list.h b/lib/list.h
index 55e0d0a..786b176 100644
--- a/lib/list.h
+++ b/lib/list.h
@@ -72,11 +72,11 @@ bool list_is_short(const struct list *);
     for (ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.prev, MEMBER);           \
          &(ITER)->MEMBER != (LIST);                                     \
          ASSIGN_CONTAINER(ITER, (ITER)->MEMBER.prev, MEMBER))
-#define LIST_FOR_EACH_SAFE(ITER, NEXT, MEMBER, LIST)            \
-    for (ASSIGN_CONTAINER(ITER, (LIST)->next, MEMBER);          \
-         (&(ITER)->MEMBER != (LIST)                             \
-          ? ASSIGN_CONTAINER(NEXT, (ITER)->MEMBER.next, MEMBER) \
-          : 0);                                                 \
+#define LIST_FOR_EACH_SAFE(ITER, NEXT, MEMBER, LIST)               \
+    for (ASSIGN_CONTAINER(ITER, (LIST)->next, MEMBER);             \
+         (&(ITER)->MEMBER != (LIST)                                \
+          ? ASSIGN_CONTAINER(NEXT, (ITER)->MEMBER.next, MEMBER), 1 \
+          : 0);                                                    \
          (ITER) = (NEXT))
 
 #endif /* list.h */
diff --git a/lib/util.h b/lib/util.h
index 2159594..911ad32 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -189,9 +189,9 @@ is_pow2(uintmax_t x)
  * that that OBJECT points to, assigns the address of the outer object to
  * OBJECT, which must be an lvalue.
  *
- * Evaluates to 1. */
+ * Evaluates to (void) 0 as the result is not to be used. */
 #define ASSIGN_CONTAINER(OBJECT, POINTER, MEMBER) \
-    ((OBJECT) = OBJECT_CONTAINING(POINTER, OBJECT, MEMBER), 1)
+    ((OBJECT) = OBJECT_CONTAINING(POINTER, OBJECT, MEMBER), (void) 0)
 
 #ifdef  __cplusplus
 extern "C" {
-- 
1.7.9.5