Interesting Topic Related to API

Hi friend
this is an interesting topic on Api Concept E_books Related to that Check it and notify me is it helpful link aur not.Suggest me.How it can be helpful.
Link to Go For Tutorial:- http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=/apis/concept.htm


Regards:-
Kaushik Jha