CERT C: Rec. INT12-C

Do not make assumptions about the type of a plain int bit-field when used in an expression

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Description

Rule Definition

Do not make assumptions about the type of a plain int bit-field when used in an expression.¹

Polyspace Implementation

The rule checker checks for Bit-field declared without appropriate type.

Examples

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Bit-field declared without appropriate type

Issue

The issue occurs when you declare a bit-field without an appropriate type.

Risk

Using int is implementation-defined because bit-fields of type int can be either signed or unsigned.

The use of enum, short char, or any other type of bit-field is not permitted in C90 because the behavior is undefined.

In C99, the implementation can potentially define other integer types that are permitted in bit-field declarations.

Check Information

Group: Rec. 04. Integers (INT)

Version History

Introduced in R2019a

¹ This software has been created by MathWorks incorporating portions of: the “SEI CERT-C Website,” © 2017 Carnegie Mellon University, the SEI CERT-C++ Web site © 2017 Carnegie Mellon University, ”SEI CERT C Coding Standard – Rules for Developing safe, Reliable and Secure systems – 2016 Edition,” © 2016 Carnegie Mellon University, and “SEI CERT C++ Coding Standard – Rules for Developing safe, Reliable and Secure systems in C++ – 2016 Edition” © 2016 Carnegie Mellon University, with special permission from its Software Engineering Institute.

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