MISRA C:2023 Rule 6.1
Bit-fields shall only be declared with an appropriate type
Since R2024a
Description
Rule Definition
Bit-fields shall only be declared with an appropriate type1 .
Rationale
Using int for a bit-field type 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.
Polyspace Implementation
The checker flags data types for bit-fields other than these allowed types:
C90:
signed intorunsigned int(ortypedef-s that resolve to these types)C99:
signed int,unsigned intor_Bool(ortypedef-s that resolve to these types)
The results depend on the version of the C standard used in the analysis. See
C standard version
(-c-version).
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: Types |
| Category: Required |
| AGC Category: Required |
Version History
Introduced in R2024a
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++:2008
MISRA C++:2023
MISRA and MISRA C are registered trademarks of The MISRA Consortium Limited 2021.
