Tense

I want to ask: What's the Use/meaning for a question in Present Perfect tense? e.g. Have you had your lunch?   Does it mean Did you have lunch before Or maybe the person is asking from "after breakfast" to "now" (include the moment of speaking), in this whole period, have you had your lunch since after breakfast?

Thanks for replies.

Have you had your lunch?
Of course, this does NOT mean
have you ever had a lunch?

And of course, such a question is asked around lunch time (say from 11am to 4pm), when one is expected to have his lunch. Which means, of course, that it's during all this period after breakfast, isn't it?

It's not a question about other days, it's a question about today. You might have had or mightn't have had breakfast, though. Perhaps you're on an empty stomach (you don't have money or time for breakfast) at the time of the question.

It means: have you had lunch today, possibly since your last breakfast (if you had one)?