-Sets path for storing temporary files (cached binary versions of index and contents files. These binary
-forms are much faster to read.) Default value is empty string (empty string means
-that no cached data are stored). Note that these files are NOT
-deleted when program exits!
+Sets the path for storing temporary files - cached binary versions of index and contents files. These binary
+forms are much faster to read. Default value is empty string (empty string means
+that no cached data are stored). Note that these files are {\it not}
+deleted when program exits.
+
+Once created these cached files will be used in all subsequent executions
+of your application. If cached files become older than corresponding .hhp
+file (e.g. if you regenerate documentation) it will be refreshed.