How Single App Binary Supports 64-bit and 32-bit Apps

Question

We can see apple announcement here.. According to this doc, we can submit same binary with supporting 32-bit and also 64-bit. I found one stack overflow answer here. But Accordi

Answer 1

At a high level, here are the steps to create an app that targets both the 32-bit and the 64-bit runtime environments:

Install Xcode 5.0.2 (I have done with this only, maybe higher is better)

Open your project. Xcode prompts you to modernize your project. Modernizing the project adds new warnings and errors that are important when compiling your app for 64-bit.

Update your project settings to support iOS 5.1.1 or later. You can’t build a 64-bit project if it targets an iOS version earlier than iOS 5.1.

Change the Architectures build setting in your project to “Standard Architectures (including 64-bit).”

Update your app to support the 64-bit runtime environment. The new compiler warnings and errors will help guide you through this process. However, the compiler doesn’t do all of the work for you; use the information in this document to help guide you through investigating your own code.

Test your app on actual 64-bit hardware. iOS Simulator can also be helpful during development, but some changes, such as the function calling conventions, are visible only when your app is running on a device.

Use Instruments to tune your app’s memory performance. Submit an app that includes both architectures for approval.

The remainder of this chapter describes problems that frequently occur when porting a Cocoa Touch app to the 64-bit runtime environment. Use these sections to guide your own efforts to investigate your code.

Follow the guide for supporting the 32 and 64 bit architecture by apple