LANG.STRUCT.ICVMF : Inappropriate Comparison of Virtual Member Function

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C and C++

LANG.STRUCT.ICVMF : Inappropriate Comparison of Virtual Member Function

Summary

A pointer to a virtual member function is tested for equality with something other than nullptr.

The result of such a comparison is unspecified.

Properties

Class Name

Inappropriate Comparison of Virtual Member Function

Significance

reliability

Mnemonic

LANG.STRUCT.ICVMF

Categories

AUTOSARC++14	AUTOSARC++14:A5-10-1	A pointer to member virtual function shall only be tested for equality with null-pointer-constant.
MisraC++2023	MisraC++2023:13.3.4	A comparison of a potentially virtual pointer to member shall only be with nullptr
CWE	CWE:758	Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
JSF++	JSF++:97.1	Neither operand of an equality operator (== or !=) shall be a pointer to a virtual member function.

Availability

Available for C++ only (not C).

Enabling

Checks for this warning class are disabled by default, and require the unnormalized C ASTs for the project. To enable them, add the following WARNING_FILTER rule and RETAIN_UNNORMALIZED_C_AST specification to the project configuration file.

RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Inappropriate Comparison of Virtual Member Function"

Note that retaining the unnormalized ASTs will increase the disk space used to store the project representation, and may make the analysis take longer.

Example

class A {
  public:
    void f1(void);
    void f2(void);
    virtual void f3(void);
};

extern bool b1, b2;

void inappropriate_comparison(void) {
    b1 = &A::f2 == &A::f3; // 'Inappropriate Comparison of Virtual Member Function' warning issued here
}

void ok_comparisons(void) {
    b1 = &A::f1 != &A::f2;           // ok: both are non-virtual
    b2 = &A::f3 == nullptr;          // ok: comparison with nullptr
}

Relevant Configuration File Parameters

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

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