iOS Is it possible to make a function that constantly tracks a location of the app user

Hello,

Sorry if my question will sound stupid. I don't have a knowledge in IOS programming, however I would like to ask one hypothetical question and hear the answer whether it's technically possible.

Would I be able to make an app with the function that could allows it's users to track each others location 24/7. I mean, in all cases, either the user is using that app or the app works just in the background.

For example, if my friend installs app and leave it to work in the background, would I be able to program function, which would allow to track his locations 24/7? (of course with all his permissions, setting and etc.)?

Thank you for the answers in advance!

Thank you for the answer.

I believe that "find my friends" wouldn't be a perfect example, because as you've said it might trigger a push and, of course, it's made by Apple (as I know apple restricts some functions for the developers).

Actually I'm planning to develop app that could allow it's users to see other app users in the map, who are nearly them (0,5 miles spread). So, as I understand that app should have a function that tracks it's users location and provide information whether there are some of them nearly you.

Is it technically possible? For example, if other users use this app in the background?

Thanks for the answers. Yes, I ono Glympse, but tracking function is just a tiny part of what I'm thinking. Thanks again!