| Synopsis: | Identifiers reserved by Standard C must not be used. |
| Language: | C |
| Severity Level: | 2 |
| Category: | LEXICAL CONVENTIONS |
| Description: |
| This leads to undefined behaviour. The complete list is available in section 4.1.2.1 of the ANSI version of Standard C, but amongst other things, includes any identifier beginning with an underscore '_'. |