LANG.TYPE.BFSHORT : Bit-field Too Short

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A bit-field has (explicitly or implicitly) signed type and width 1.

Class Name

Bit-field Too Short

Significance

style

Mnemonic

LANG.TYPE.BFSHORT

Categories

MisraC2023	MisraC2023:6.2	Single-bit named bit fields shall not be of a signed type
Misra2012	Misra2012:6.2	Single-bit named bit fields shall not be of a signed type
Misra2004	Misra2004:6.5	Bit fields of signed type shall be at least 2 bits long
AUTOSARC++14	AUTOSARC++14:M9-6-4	Named bit-fields with signed integer type shall have a length of more than one bit.
MisraC++2008	MisraC++2008:9-6-4	Named bit-fields with signed integer type shall have a length of more than one bit.
MisraC++2023	MisraC++2023:12.2.1	Bit fields should not be declared
	MisraC++2023:12.2.3	A named bit-field with signed integer type shall not have a length of one bit

Availability

Available for C and C++.

Enabling

Checks for this warning class are disabled by default, and require the unnormalized C ASTs for the project. To enable them, add the following WARNING_FILTER rule and RETAIN_UNNORMALIZED_C_AST specification to the project configuration file.

RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Bit-field Too Short"

Note that retaining the unnormalized ASTs will increase the disk space used to store the project representation, and may make the analysis take longer.

typedef int plainint;
typedef signed int signedint;
typedef unsigned int uint;

struct widthstruct{
  signed int si1      : 2;
  signed int si2      : 1; /* 'Bit-field Too Short' warning issued here */
  signedint si3       : 1; /* 'Bit-field Too Short' warning issued here */
  unsigned int si4    : 1;
  uint si5            : 1;
  int si6             : 1; /* 'Bit-field Too Short' warning issued here */
  plainint si7        : 1; /* 'Bit-field Too Short' warning issued here */
};

The following configuration file parameters affect checks for this warning class.

LANG.TYPE.BFSHORT : Bit-field Too Short

Summary

Properties

Example

Relevant Configuration File Parameters