How to find change in open interest for current bar in realtime basis through EFS

[ANILES]

i am writing an efs to find out change in open interest of ?


I did not find anything from below ink.

http://kb.esignal.com/display/2/index.aspx?c=12&cpc=ULwO0A442oKs512Q04X5j0UupP4SveI6dt2WJi7&cid=4&cat=&catURL=&r=0.88957542181015

How to find out that is there any function available for that?
Here is the sample code

var TOTALOI = oi(0,sym("SYMBOLNAME,D")); // TODAYS OI

var YOI = oi(-1,"SYMBOLNAME"); //yesterday oi

var TOCOI = TOTALOI - YOI;// How many opens interest added today?

2) how to get Nearest options strike of the spot through EFS? Lets assume 3 strikes of option based on spot price.

Please help.