Compiler Warning (level 1) C4946

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The latest version of this topic can be found at Compiler Warning (level 1) C4946.

reinterpret_cast used between related classes: 'class1' and 'class2'

Do not use reinterpret_cast to cast between related types. Use static_cast instead, or for polymorphic types, use dynamic_cast.

By default, this warning is off. For more information, see Compiler Warnings That Are Off by Default.

The following code example generates C4946:

// C4946.cpp  
// compile with: /W1  
#pragma warning (default : 4946)  
class a {  
public:  
   a() : m(0) {}  
   int m;  
};  
  
class b : public virtual a {  
};  
  
class b2 : public virtual a {  
};  
  
class c : public b, public b2 {  
};  
  
int main() {  
   c* pC = new c;  
   a* pA = reinterpret_cast<a*>(pC);   // C4946  
   // try the following line instead  
   // a* pA = static_cast<a*>(pC);  
}