LANG.CAST.PC.DCVBASE : Derived Class From Virtual Base

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CodeSonar^® 9.2p0

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LANG.CAST.PC.DCVBASE : Derived Class From Virtual Base

Summary

A pointer to virtual base class is cast to a pointer to a derived class by static_cast or a C-style cast.

Properties

Misra2004

Misra2004:11.4

A cast should not be performed between a pointer to object type and a different pointer to object type

AUTOSARC++14

AUTOSARC++14:M5-2-2

A pointer to a virtual base class shall only be cast to a pointer to a derived class by means of dynamic_cast.

AUTOSARC++14:A5-2-4

reinterpret_cast shall not be used.

MisraC++2008

MisraC++2008:5-2-2

A pointer to a virtual base class shall only be cast to a pointer to a derived class by means of dynamic_cast.

MisraC++2008:5-2-7

An object with pointer type shall not be converted to an unrelated pointer type, either directly or indirectly.

MisraC++2023

MisraC++2023:8.2.1

A virtual base class shall only be cast to a derived class by means of dynamic_cast

MisraC++2023:8.2.5

reinterpret_cast shall not be used

CWE

CWE:704

Incorrect Type Conversion or Cast

TS17961

TS17961:5.1-ptrcomp

Accessing an object through a pointer to an incompatible type

CERT-C

CERT-C:EXP36-C

Do not cast pointers into more strictly aligned pointer types

JSF++

JSF++:178

Down casting (casting from base to derived class) shall only be allowed through certain mechanisms.

JSF++:179

A pointer to a virtual base class shall not be converted to a pointer to a derived class.

JSF++:182

Type casting from any type to or from pointers shall not be used.

JSF++:183

Every possible measure should be taken to avoid type casting.

Example

class Base {
  public:
    virtual void polymorphic(void);
};

class Derived : public virtual Base { };

Derived d;
Derived *pD1, *pD2, *pD3;

void virtual_base_cast(void) {
    Base * pB = &d;

    /* These two casts will cause errors in many compilers.
     * We guard the statements with "#ifdef __CODESONAR__ ... #endif" so that they
     * are preprocessed out by the native compiler (so the example can be compiled)
     * but still observed by the CodeSonar analysis.
     */
#ifdef __CODESONAR__
    pD1 = (Derived *)pB;              // 'Derived Class From Virtual Base' warning issued here
    pD2 = static_cast<Derived *>(pB); // 'Derived Class From Virtual Base' warning issued here
#endif
    pD3 = dynamic_cast<Derived *>(pB);                 // ok: not static_cast or C-style cast
}

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.