static object memory release

Question

My Questing is

-(ABC*)createInstance
{
  Static ABC *obj = [[alloc ABC] init];

  if(obj == nil)
  {
    obj = [[alloc ABC] init];
  }
  return obj
}

can we write in objective c

[[ABC createInstance] release]

Answer 1

Yes, users could release your instance if you haven't overridden retain/release. Take a look at common singleton patterns for better approaches.

Notes:

• It is [ClassName alloc], not [alloc ClassName]
• If you meant to make createInstance a class method use + (ABC*)createInstance;
• It is static, not Static
• You have to initialize obj to nil
• Use self instead of ABC if subclassing is a concern: [self alloc]
• The common name for these methods is sharedInstance