MISRA.PUREVIRT.OVRD

Pure virtual function overrides a non pure virtual function.

MISRA-C++ Rule 10-3-3 (required): A virtual function shall only be overridden by a pure virtual function if it is itself declared as pure virtual.

Rationale

Re-declaring a function as pure may not meet developer expectations.

Example

class A

{
public:
   virtual void foo ( ) = 0;   // foo declared pure
};

class B : public A
{
public:
   virtual void foo ( )        // foo defined
   {
   }
};

class C: public B
{
public:
   virtual void foo ( ) = 0;   // Non-compliant — foo re-declared pure
};

The function 'foo' is introduced as pure (making class 'A' abstract), defined in class 'B' (making class 'B' concrete), then re-declared as pure (making class 'C' abstract). As this may not meet developer expectations, the re-declaration as pure is not allowed.