specify when destructors are called

Author: vladak

threads.tex

@@ -546,12 +546,12 @@
 place per thread with minimal changes to the original code.
 \item When you create a key, the \texttt{NULL} value is associated with it.
 \item If you do not need the destructor function, use \texttt{NULL}.
-\item Destructors are called in unspecified order on all keys with a value
-different from \texttt{NULL}.  Its value is set to \texttt{NULL} and the
-original value is used as a parameter to the destructor.  If, after all the
-destructors have been called for all non-\texttt{NULL} values with associated
-destructors, there are still some non-\texttt{NULL} values with associated
-destructors, then the process is repeated.  If, after at least
+\item Destructors are called at thread exit in unspecified order on all keys
+with a value different from \texttt{NULL}.  Its value is set to \texttt{NULL}
+and the original value is used as a parameter to the destructor.  If, after
+all the destructors have been called for all non-\texttt{NULL} values with
+associated destructors, there are still some non-\texttt{NULL} values with
+associated destructors, then the process is repeated.  If, after at least
 \texttt{PTHREAD\_DESTRUCTOR\_ITERATIONS} iterations of destructor calls for
 outstanding non-NULL values, there are still some non-\texttt{NULL} values with
 associated destructors, the implementation may (it usually does otherwise you