# V2637. MISRA. A 'noreturn' function should have 'void' return type.

This diagnostic rule is based on the MISRA (Motor Industry Software Reliability Association) software development guidelines.

This diagnostic rule is relevant only for C.

A function declared with the `_Noreturn` specifier (C11) or the `[[noreturn]]` attribute (C23) must not return control flow to the calling function, otherwise the behavior is undefined. So, it cannot return any value after being called, and it must be of the `void` return type.

The analyzer issues a warning when it detects a `noreturn` function having a return type other than `void`. This code is suspicious and may indicate a typo or design error.

The code example where the analyzer issues a warning:

    _Noreturn int sum(int a, int b) // _Noreturn is a typo
    {
      return a + b; // undefined behavior
    }

In this case, a developer accidentally added the `_Noreturn` specifier. To remove the analyzer warning, delete the redundant specifier:

    int sum(int a, int b)
    {
      return a + b;
    }

This diagnostic is classified as:

MISRA-C-2023-17.10