MISRA C:2012 Rule 16.1

All switch statements shall be well-formed

Description

Rule Definition

All switch statements shall be well-formed¹

Rationale

The syntax for switch statements in C is not particularly rigorous and can allow complex, unstructured behavior. This rule and other rules impose a simple consistent structure on the switch statement.

Polyspace Implementation

Following the MISRA™ specifications, the coding rules checker also raises a violation of rule 16.1 if a switch statement violates one of these rules: 16.2, 16.3, 16.4, 16.5 or 16.6.

Additional Message in Report

All messages in report file begin with "MISRA-C switch statements syntax normative restriction."

• Initializers shall not be used in switch clauses.

• The child statement of a switch shall be a compound statement.

• All switch clauses shall appear at the same level.

• A switch clause shall only contain switch labels and switch clauses, and no other code.

• A switch statement shall only contain switch labels and switch clauses, and no other 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: Switch Statements

Category: Required

AGC Category: Advisory

Version History

R2024a: Default case containing no statement or comment other than break;

The rule checker does not report a violation when a switch statement contains a default case with no statements or comments other than break;. The default case must contain a break statement, but a statement list or comments are optional.

void example (int i) {
    switch(i) {
        case 0:
        case 1:
            i++;
            break;
        case 2:
        default:               // Compliant
            break;
    }
}