I create a project with ARC support using the Xcode project wizard. Compared with a program without ARC support, I did not notice any differences. Is there any hint that can tell me if my program supports ARC?

I am using XCode 4.2.1 Build 4D502
['https://Stackoverflow.com/questions/11380533', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/705414/']
You can use `__has_feature`, maybe logging whether the project has ARC in the console like this:

```
#if __has_feature(objc_arc)
    // ARC is On
    NSLog(@"ARC on");

#else
    // ARC is Off
    NSLog(@"ARC off");

#endif

```

Alternatively, instead of just logging whether ARC is on, try making the compiler raise an error if ARC is on (or off) like this:

```
#if  ! __has_feature(objc_arc)
    #error This file must be compiled with ARC. Use -fobjc-arc flag (or convert project to ARC).
#endif

```
add "-fno-objc-arc" compiler flags for all the .m files in build phases