Reason to use ivars vs properties in objective c

Question

I have been unable to find any information on this topic and most of what I know about it has come by complete accident (and a few hours of trying to figure out why my code

Answer 1

This may be an old question.. but in "modern times", @synthesize- is NOT necessary.

@interface       SomeClass : NSObject
@property NSString * autoIvar;
@end
@implementation  SomeClass
- (id) init { return self = super.init ? _autoIvar = @"YAY!", self : nil; }
@end

The _underscored backing ivar IS synthesized automatically... and is available within THIS class' implementation, directly (ie. without calling self / calling the automatically generated accessors).

You only need to synthesize it if you want to support subclass' ability to access the _backingIvar (without calling self), or for myriad other reasons, described elsewhere.