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The difference between _var and self.var

When all this new ARC material (which does not fall under NDA ...), it seems that by default to work with properties you should set the property without and ivar in the implementation file explicitly until you synthesize it with something like

@synthesize var = _var;

What is the best thing to use when setting up a variable? I know that the difference between varand self.varis that it self.varuses dot notation and uses the set var method.

Is it _varequivalent to setting it in header files, for example, on good days? Where did this practice of anticipating everything come from with underlining?

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2 answers

_var - (, , ). , , ivar.

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@property : @property (nonatomic, strong) NSString *var;, Objective-C 2.0 , 2012 , @synthesize :

  • NSString *_var.
  • : -(NSString *)var {}
  • : -(void)setVar:(NSString *)newVar {}

, - KVO , getter setter.

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