I want to bring a single Objective-C class written using ARC into an old project. The internet provides many references for how to enable ARC for your project and then disable it for single files but I want to do the opposite.
I want to leave the project as it is, i.e. using manual reference counting, and then enable ARC just for the new file. (My searches have failed me here.)
Is this possible? How?
Add the -fobjc-arc flag to any files for which you'd like to enable ARC, as described in the ARC documentation.
Select Target > Build Phases > Compile Source > Select Your class > Double Click> Type
-fobjc-arc in dialog box
Enter.
来源：https://stackoverflow.com/questions/10523816/how-to-enable-arc-for-a-single-file