Everything is in the title:
by Glennan Carnie
From the article:
Previously, we’ve looked at The Rule of Zero which, in essence, says: avoid doing your own resource management; use a pre-defined resource-managing type instead.
This is an excellent guideline and can significantly improve the quality of your application code. However, there are some circumstances where you might not get exactly what you were expecting. It’s not that the code will fail; it just might not be as efficient as you thought.
Luckily, the solution is easy to implement and has the additional side-effect of making your code even more explicit.