- Add some comments on thread storage with a brief explanation of what it is

as well as what the motivation is for using it.
- Add a comment by the declaration of ast_inet_ntoa() noting that this function
  is not reentrant, and the result of a previous call to the function is no
  longer valid after calling it again.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@48019 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/utils.h

@@ -218,6 +218,16 @@ static force_inline void ast_slinear_saturated_divide(short *input, short *value
 
 int test_for_thread_safety(void);
 
+/*!
+ * \brief thread-safe replacement for inet_ntoa().
+ *
+ * \note It is very important to note that even though this is a thread-safe
+ *       replacement for inet_ntoa(), it is *not* reentrant.  In a single
+ *       thread, the result from a previous call to this function is no longer
+ *       valid once it is called again.  If the result from multiple calls to
+ *       this function need to be kept or used at once, then the result must be
+ *       copied to a local buffer before calling this function again.
+ */
 const char *ast_inet_ntoa(struct in_addr ia);
 
 #ifdef inet_ntoa