double check locking in singleton pattern

Question

it may be basic question

to have a singleton in multi-threaded environment we can use a lock. Please refer the code snippet. But why do we need double-checked locki

Answer 1

If you create the object in the field initialiser, you don't need the lock:

class singleton
{
    private static singleton instance = new singleton();
    private static singleton() { }

    public static singleton Instance
    {
        get { return instance; }
    }
}

Also - bear in mind that the lock is only controlling the creation of the object, the object would still need to be thread-safe if you're using it in multiple threads.