# V2607. MISRA. Inline functions should be declared with the static storage class.

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

This rule is only relevant to C. Functions with the 'inline' qualifier must be declared with the 'static' qualifier.

If an inline function with 'external linkage' is declared in a translation unit but is not defined in this translation unit, this will result in undefined behavior.

Even an 'inline' function with 'external linkage' that is declared and called in one translation unit may cause a problem. Such a call is unspecified behavior. The compiler can generate a function call or embed the body of that function instead of the call. Although this will not affect the called function behavior, it can impact the program runtime and thus affect the program during its execution.

Code example that the analyzer will issue a warning for:

    #include <stdint.h>

    extern inline int64_t sum(int64_t lhs, int64_t rhs);

    extern inline int64_t sum(int64_t lhs, int64_t rhs)
    {
      return lhs + rhs;
    };

This diagnostic is classified as:

MISRA-C-2012-8.10 MISRA-C-2023-8.10