ENH: Clarified search behavior when the objective is not found.

Source/cmFindBase.cxx

@@ -57,8 +57,13 @@ cmFindBase::cmFindBase()
     ""
     "This command is used to find a SEARCH_XXX_DESC. "
     "A cache entry named by <VAR> is created to store the result "
-    "of this command.  If nothing is found, the result will be "
-    "<VAR>-NOTFOUND.  The name of the SEARCH_XXX that "
+    "of this command.  "
+    "If the SEARCH_XXX is found the result is stored in the variable "
+    "and the search will not be repeated unless the variable is cleared.  "
+    "If nothing is found, the result will be "
+    "<VAR>-NOTFOUND, and the search will be attempted again the "
+    "next time FIND_XXX is invoked with the same variable.  "
+    "The name of the SEARCH_XXX that "
     "is searched for is specified by the names listed "
     "after the NAMES argument.   Additional search locations "
     "can be specified after the PATHS argument.  If ENV var is "