MISRA C:2025 Rule 20.10

R2026b

The # and ## preprocessor operators should not be used

Since R2026b

Description

The # and ## preprocessor operators should not be used 1 .

Rationale

The order of evaluation associated with multiple #, multiple ##, or a mix of # and ## preprocessor operators is unspecified. In some cases, it is therefore not possible to predict the result of macro expansion.

The use of ## can result in obscured code.

Troubleshooting

If you expect a rule violation but do not see it, refer to Diagnose Why Coding Standard Violations Do Not Appear as Expected.

Check Information

Group: Preprocessing Directives
Category: Advisory
AGC Category: Advisory
PQL Name: std.misra_c_2025.R20_10

Version History

Introduced in R2026b

See Also

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Topics

1 All MISRA coding rules and directives are © Copyright The MISRA Consortium Limited 2021.

The MISRA coding standards referenced in the Polyspace® Bug Finder™ documentation are from the following MISRA standards:

  • MISRA C:2004

  • MISRA C:2012

  • MISRA C:2023

  • MISRA C:2025

  • MISRA C++:2008

  • MISRA C++:2023

MISRA and MISRA C are registered trademarks of The MISRA Consortium Limited 2021.