What calls the Apple store login view

I have setup in app purchases and I would like to display the apple store login page once the user decides to buy an item.

What calls or displays the开发者_StackOverflow中文版 alert/login view?

Is it build into the SKRequest?

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Yes, that's built-in. The user will be asked for credentials when you add a new payment to the payment queue.

[[SKPaymentQueue defaultQueue] addPayment:payment];