Added useful comments

git-svn-id: https://svn.origo.ethz.ch/eiffelstudio/trunk/Src/library/cURL@81175 8089f293-4706-0410-a29e-feb5c42a2edf

curl_function.e

@@ -4,6 +4,10 @@ note
 						We need this class since cURL need a c function pointer as value but
 						Eiffel function need frist parameter of any funciton call is object address.
 						Client programmers can inherit this class to fit their needs.
+
+						Note: descendants of this class have to call `set_object_and_function_address',
+						otherwise cURL would not know how to call Eiffel features (such as `write_function').
+						See example: $ISE_LIBRARY\examples\cURL\upload_and_read_function						
 																											]"
 	status: "See notice at end of class."
 	legal: "See notice at end of class."