NSAutoreleasePool的官方解释
Important If you use Automatic Reference Counting (ARC), you cannot use autorelease pools directly. Instead, you use @autoreleasepool blocks instead. For example, in place of:
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init; // Code benefitting from a local autorelease pool. [pool release];
you would write:
@autoreleasepool {
// Code benefitting from a local autorelease pool.
}
@autoreleasepool blocks are more efficient than using an instance of NSAutoreleasePool directly; you can also use them even if you do not use ARC.
xcode4.3引入ARC，release这块就有些变化，当你使用ARC，就必须将NSAutoreleasePool的地方换成 @autoreleasepool
http://marshal.easymorse.com/archives...
兩者的作用時間不一樣。 AutoReleasePool物件的寫法作用於執行時，@autoreleasepool作用於編譯階段。如果要啟用ARC的話，在編譯階段就需要告訴編譯器啟用自動引用計數管理，而不能在執行時動態新增。
現在蘋果推薦都使用@autoreleasepool{},無論是否使用ARC