CERT.EXPR.PASS_NON_STD_LAYOUT

Do not pass a nonstandard-layout type object across execution boundaries.

Vulnerability and risk

Standard-layout types can be used to communicate with code written in other programming languages, as the layout of the type is strictly specified.

Non-standard-layout types should not be used because different languages and different compiler versions may align member data differently.

This checker looks for function calls where the called function is declared "extern" with a linkage specifier that is not "C++". If a nonstandard-layout object is passed then a violation is reported.

Mitigation and prevention

Don't pass nonstandard-layout objects to functions defined in other languages.

Example

Copy 
  struct B {
    int i, j;
  };
  
  struct D : B {
    float f;
  };
  
  extern "C" void func(void *);
  
  void foo(D *d) {
    func(d);
  }

A vilolation will be reported on line 12.

External guidance