# V2585. MISRA. Casts between a void pointer and an arithmetic type should not be performed.

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

This rule only applies to programs written in C. A cast between a variable or an arithmetic type literal and 'void *' may cause undefined (for floating-point numbers) or platform-specific behavior (for integer types).

Consider the first synthetic example:

    void* foo(void)
    {
      double pi = 3.14;
      return pi;
    }

In this case, the double 'pi' variable is implicitly cast to 'void *'. Such code will lead to undefined behavior.

Take a look at the second synthetic example:

    void bar(void)
    {
      int a = 5;
      void* b = (void*)a;
    }

Here the 'int' variable is explicitly cast to the 'void *' pointer. Further dereferencing of such a pointer may lead to segfault.

This diagnostic is classified as:

MISRA-C-2012-11.6 MISRA-C-2023-11.6