Why doesn't this common property initialization scheme risk failure when the synthesized setter tries to release the undefined myArray object? Or are property objects automatically initialized to nil and I don't need to be doing this at all?
@interface myClass : NSObject {
NSArray* myArray;
}
@property (nonatomic, retain) NSArray* myArray;
@end
@implementation myClass
@synthesize myArray;
-(id)init {
if ( self = [super init] ) {
self.myArray = nil;
}
return self;
}
...
Object instance variables in Objective-C are initialized to nil by default. Furthermore, messaging nil is allowed (unlike calling a method on null in function-calling languages like Java, C# or C++). The result of a message to nil is nil, this calling [nil release]; is just nil, not an exception.
On a side note, it's best practice to assign/call instance variables directly in -init and -dealloc methods:
-(id)init {
if ( self = [super init] ) {
myArray = nil;
}
return self;
}
- (void)dealloc {
[myArray release];
[super dealloc];
}
As others have stated, the instance variable is already initialised to nil.
Additionally, as per Apple's documentation, instance variables should be set directly in an init method, as the getter/setter methods of a class (or subclass thereof) may rely on a fully initialised instance.
It's already initialized to nil.
