How to enable/disable ARC in an xcode project?

问题

If a project has already been created with ARC disabled, how do I enable it and vice versa?

回答1:

Open your project and select Edit -> Refactor -> Convert to Objective-C ARC. This will start checking your code if it is ready for the conversion.

Good link to read: Everything you need to know about automatic reference counting (ARC)

How to disable ARC has been answered here

回答2:

Following are the steps which I did and it worked for me

1. Select Project
2. Select Targets
3. From the right panel, select Build Settings
4. Search for "Automatic Reference Counting";
5. Locate Apple LLVM compiler 3.0 - Language and Objective-C Automatic Reference Counting and select NO in all three sections.

回答3:

When you migrate a project to use ARC, the -fobjc-arc compiler flag is set as the default for all Objective-C source files. You can disable ARC for a specific class using the -fno-objc-arc compiler flag for that class. In Xcode, in the target Build Phases tab, open the Compile Sources group to reveal the source file list. Double-click the file for which you want to set the flag, enter -fno-objc-arc in the pop-up panel, then click Done.

回答4:

In Xcode 5.0.2, select your project in Navigatior, select Build Settings, search for Apple LLVM 5.0 - Language - Objective C and change Objective-C Automatic Refence Counting to NO

来源：https://stackoverflow.com/questions/9018366/how-to-enable-disable-arc-in-an-xcode-project