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MISRA C:2023 Rule 23.8

A default association shall appear as either the first or the last association of a generic selection

Since R2024a

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Description

Rule Definition

A default association shall appear as either the first or the last association of a generic selection.

This rule comes from MISRA C™: 2012 Amendment 3.

Rationale

The code is easier to read and understand when the default association is either the first or the last association in a generic selection.

Polyspace Implementation

Polyspace® reports a violation of this rule if the default association of a _Generic statement is neither the first nor the last association.

Troubleshooting

If you expect a rule violation but do not see it, refer to Diagnose Why Coding Standard Violations Do Not Appear as Expected.

Examples

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In this example, the default association is neither the first nor the last association of get_type_id. Polyspace reports a violation of this rule.

 #define get_type_id(x) ( _Generic((x) /* Noncompliant */ \
                        , char : 0       \
                        , default : 3    \
	                    , int  : 1      ))


void foo() {
	int x, y;
	y = get_type_id(x);
}

Check Information

Group: Generic Selections
Category: Required
AGC Category: Required

Version History

Introduced in R2024a

See Also

Topics