摘要：
nonatomic vs. atomic - "atomic" is the default. Always use "nonatomic". I don't know why, but the book I read said there is "rarely a reason" to use "atomic". (BTW: The book I read is the BNR "iOS Programming" book.)readwrite vs. readonly - " 阅读全文
摘要：
在很多代码里可以看到类似得用法：@interface MyClass:NSObject{ MyObjecct *_object;}@property(nonamtic, retain) MyObjecct *object;@end@implementatin MyClass@synthesize object=_object; （1）32位系统和64位系统的差异 在32位系统中，如果类的@interface部分没有进行ivar（instance variable）声明，但有@property声明，在类的@implementation部分有响应的@synthesize，则会... 阅读全文