C++ Coding Standards: 101 Rules, Guidelines, and Best Practices

65. Customize intentionally and explicitly

Summary

Intentional is better than accidental, and explicit is better than implicit: When writing a template, provide points of customization knowingly and correctly, and document them clearly. When using a template, know how the template intends for you to customize it for use with your type, and customize it appropriately.

Discussion

A common pitfall when writing template libraries is providing unintentional points of customization—that is, points where a caller’s code can get looked up and used inside your template, but you didn’t mean for a caller’s code to get involved. It’s easy to do: Just call another function or operator the normal way (unqualified), and if one of its arguments happens to ...