timeIntervalSince1970
is a class method of NSDate
. If you want to get the current time every screenshot you can use as a unique identifier you can do something like this.
NSString * s = [NSString stringWithFormat:@"awesomeshot%@.jpg", [NSDate date]];
C4Log(@"%@",s );
If you really want to use timeIntervalSince1970
you can check out this discussion: How to convert NSDate into unix timestamp iphone sdk?