Lowercase letter l (ell) can easily be confused with the digit 1 (one). This can be particularly confusing when indicating that an integer literal constant is a long value. This recommendation is similar to DCL02-C. Use visually distinct identifiers. Likewise, you should use uppercase LL rather than lowercase ll when indicating that an integer literal constant is a long long value.
To be precise when using modifiers to indicate the type of an integer literal, the first character may not be l. It may be L, u, or U. Subsequent characters have no strict case requirements.
Noncompliant Code Example
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Tool | Version | Checker | Description | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Astrée |
| long-suffix | Fully checked | |||||||||||||
| Axivion Bauhaus Suite |
| CertC-DCL16 | ||||||||||||||
| CodeSonar |
| LANG.TYPE.CSUF | Confusing literal suffix | |||||||||||||
| CC2.DCL16 | Fully implemented | ||||||||||||||
| Helix QAC |
| C1280 | ||||||||||||||
| LDRA tool suite |
| 252 S | Fully implemented | |||||||||||||
| Parasoft C/C++test |
| PORT-01 | Fully implemented | PRQA QA-C | ||||||||||||
| Include Page | PRQA QA-C_v | PRQA QA-C_v | 1280 | CERT_C-DCL16-a | The lowercase form of 'L' shall not be used as the first character in a literal suffix | |||||||||||
| PC-lint Plus |
| 620 | Fully supported | |||||||||||||
| Polyspace Bug Finder |
| CERT C: Rec. DCL16-C | Checks for use of lowercase "l" in literal suffix (rec. fully covered)Fully implemented | |||||||||||||
| RuleChecker |
| long-suffix | Fully checked | |||||||||||||
| SonarQube C/C++ Plugin |
| LiteralSuffix |
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