Obj-C @synthesize [duplicate]

Answer 1

n .h

    UILabel *_detailDescriptionLabel;
}
    @property (strong, nonatomic) IBOutlet UILabel *detailDescriptionLabel;

in .m

@synthesize detailDescriptionLabel = _detailDescriptionLabel;

This line means that the property "detailDescriptionLabel" will have a setter and getter for the class attribute named "_detailDescriptionLabel"

If the name was the same, you will have

@synthesize detailDescriptionLabel;

Answer 2

Each property is backed by an instance variable. The language allows for them to be named differently. By doing @synthesize detailDescriptionLabel = _detailDescriptionLabel;, you're basically saying that use _detailDescriptionLabel as the backing instance variable for the property detailDescriptionLabel. If you just do @synthesize detailDescriptionLabel;, it implicitly understands that the instance variable has the same name.