object-c ARC

xcode不断进步，在xcode4中引入了ARC的概念。您用或者不用它就在那里，于是有了本文:如何在未使用arc的工程中引入一个使用了arc特性的文件，如何在arc工程中引用未使用arc的文件。其实说白了也很简单就是在”Compile Sources”中对相应的文件加入使用或者不使用arc的flag
ok,首选“Compile Sources”的位置:选中工程->TARGETS->相应的target然后选中右侧的“Build Phases”，向下就找到“Compile Sources”了。
如何在未使用arc的工程中引入一个使用了arc特性的文件:对相应的文件添加:-fobjc-arc参数

如何在arc工程中引用未使用arc的文件:对相应的文件添加:-fnoobjc-arc参数

I'm trying to compile using the LLVM GCC 4.0 compiler, and I get this error in multiple of my .m files: ARC forbids explicit message send of 'release'I've tried using -fno-objc-arc as a compiler flag but that returns the error: Unrecognized command line option "-fno-objc-arc".

Simply remove all calls to -release. You're not allowed to call -release under ARC because the compiler will insert all the necessary retain/release calls for you. Read more about ARC here.

The other way is to use the conversion tool, and Xcode can convert your project to ARC (including removing these calls) for you:

To disable ARC entirely, change your build settings:

However I'd recommend you start using ARC, it will make things a lot easier and actually faster too.