LANG.STRUCT.SW.MD : Missing default

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CodeSonar^® 9.2p0

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C and C++

LANG.STRUCT.SW.MD : Missing default

Summary

A switch statement does not contain a default label.

This class is a strict subset of Malformed switch Statement.

If a switch statement exhibits multiple issues from the following list, the analysis may report only a subset of them.

Properties

Class Name

Missing default

Significance

style

Mnemonic

LANG.STRUCT.SW.MD

Categories

MisraC2025	MisraC2025:16.4	Every switch statement shall have a default label
MisraC2023	MisraC2023:16.4	Every switch statement shall have a default label
Misra2012	Misra2012:16.4	Every switch statement shall have a default label
Misra2004	Misra2004:15.3	The final clause of a switch statement shall be the default clause
AUTOSARC++14	AUTOSARC++14:M6-4-6	The final clause of a switch statement shall be the default-clause.
MisraC++2008	MisraC++2008:6-4-6	The final clause of a switch statement shall be the default-clause.
MisraC++2023	MisraC++2023:9.4.2	The structure of a switch statement shall be appropriate
CWE	CWE:478	Missing Default Case in Multiple Condition Expression
TS17961	TS17961:5.17-swtchdflt	Use of an implied default in a switch statement
JSF++	JSF++:194	All switch statements that do not intend to test for every enumeration value shall contain a final default clause.
OWASP-2025	OWASP-2025:A10	Mishandling of Exceptional Conditions

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="Missing default"

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

Example

void lang_struct_sw_md(int i){

    switch (i){                                     /* contains a default clause */
        case 1: {/* ... */ break;}
        case 2: {/* ... */ break;}
        default: {/* ... */ break;}
    }

    switch (i){                  /* 'Missing default' warning issued here */
        case 1: {/* ... */ break;}
        case 2: {/* ... */ break;}
        case 3: {/* ... */ break;}
    }
}

Relevant Configuration File Parameters

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

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