MISRA C:2012 Rule 17.11

A function that never returns should be declared with a _Noreturn function specifier

Since R2024a

Description

A function that never returns should be declared with a _Noreturn function specifier¹ .

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

Rationale

If a function that does not return to its caller is not declared with a _Noreturn specifier, it is unclear whether it intentionally does not return, or does not return due to an error in the program logic.

Polyspace Implementation

The rule checker reports a violation if there are no return paths from a function to its caller but the function is not declared with a _Noreturn specifier.

As an exception, Polyspace^® does not report a violation if main() is not declared as _Noreturn.

This checker reports a rule violation only if you specify the C language standard as C11 or later for the Bug Finder analysis. For more information, 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.

Examples

Function Not Declared _Noreturn Does Not Return to Caller

In this example, the function checkID() is declared with a _Noreturn specifier. The functions verifyID() and assessID() both call checkID() and therefore cannot return to their callers.

• The function verifyID() is not declared with a _Noreturn specifier, therefore violates the rule.

• The function assessID() is declared with a _Noreturn specifier, and does not violate the rule.

#include <stdint.h>

_Noreturn void checkID(int32_t ID);

void verifyID(int32_t ID) { //Noncompliant
    checkID(ID);
}

_Noreturn void assessID(int32_t ID) { //Compliant
    checkID(ID);
}

Check Information

Group: Functions

Category: Advisory

AGC Category: Advisory

PQL Name: std.misra_c_2012.R17_11

Version History

Introduced in R2024a

R2026a: Violation no longer reported on main()

Polyspace no longer reports a violation if main() is declared without using the _Noreturn attribute.