make AST_LIST_REMOVE_HEAD safer to use

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6394 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/include/asterisk/linkedlists.h b/include/asterisk/linkedlists.h
index b4085d7..72f1975 100755 (executable)
--- a/include/asterisk/linkedlists.h
+++ b/include/asterisk/linkedlists.h
@@ -305,14 +305,15 @@ struct {                                                          \
   \param field This is the name of the field (declared using AST_LIST_ENTRY())
   used to link entries of this list together.
 
-  Removes the head entry from the list, and returns a pointer to it. The
-  forward-link pointer in the returned entry is \b not cleared. This macro
-  is safe to call on an empty list.
+  Removes the head entry from the list, and returns a pointer to it.
+  This macro is safe to call on an empty list.
  */
 #define AST_LIST_REMOVE_HEAD(head, field) ({                           \
                typeof((head)->first) cur = (head)->first;              \
-               if (cur)                                                \
+               if (cur) {                                              \
                        (head)->first = cur->field.next;                \
+                       cur->field.next = NULL;                         \
+               }                                                       \
                cur;                                                    \
        })