Include guards, wrapping around the entire content of a header file, are a best practice that ensure that no matter how many times the header is
actually included in a translation unit, its content will only be seen once.
The include guard pattern is made up of four parts:
#ifndef at the top of the file, with a unique macro name (usually the name relates to the name of the file, to ensure uniqueness).
#define with the same macro name.
- The content of the file
#endif at the end of the file
The rule raises an issue when the name in the second part differs from the name in the first (usually because of a typo or a copy/paste issue).
Noncompliant Code Example
#define MY_FILE_H // Noncompliant