AUTOSAR C++14 Rule M3-2-3
A type, object or function that is used in multiple translation units shall be declared in one and only one file
Description
Rule Definition
A type, object or function that is used in multiple translation units shall be declared in one and only one file.
Rationale
If you declare an identifier in a header file, you can include the header file in any translation unit where the identifier is defined or used. In this way, you ensure consistency between:
- The declaration and the definition. 
- The declarations in different translation units. 
The rule enforces the practice of declaring external objects or functions in header files.
Troubleshooting
If you expect a rule violation but Polyspace® does not report it, see Diagnose Why Coding Standard Violations Do Not Appear as Expected.
Check Information
| Group: Basic Concepts | 
| Category: Required, Automated | 
Version History
Introduced in R2019a