Singleton (manual reference counting)

gistfile1.m

static MyClass *sharedMyManager = nil;
 
+ (MyClass*)sharedInstance
{
    if (sharedMyManager == nil) {
        sharedMyManager = [[super allocWithZone:NULL] init];
    }
    return sharedMyManager;
}
 
+ (id)allocWithZone:(NSZone *)zone
{
    return [[self sharedInstance] retain];
}
 
- (id)copyWithZone:(NSZone *)zone
{
    return self;
}
 
- (id)retain
{
    return self;
}
 
- (NSUInteger)retainCount
{
    return NSUIntegerMax;  //denotes an object that cannot be released
}
 
- (oneway void)release
{
    //do nothing
}
 
- (id)autorelease
{
    return self;
}