Synopsis

A virtual member function is called in a class constructor.

Enabled by default

Yes

Severity/Certainty

Medium/High

Full description

When an instance is constructed, the virtual member function of its base class is called, rather than the function of the actual class being constructed. This might result in the incorrect function being called, and consequently incorrect data or uninitialized elements. This check is identical to MISRAC++2008-12-1-1_a, MISRAC++2023-15.1.1_a.

Coding standards

Code examples

The following code example fails the check and will give a warning:

#include <iostream>

class A {
public: 
  A() { f(); }  //virtual member function is called
  virtual void f() const { std::cout << "A::f\n"; }
};

class B: public A {
public:
  virtual void f() const { std::cout << "B::f\n"; }
};

int main(void) {
  B *b = new B();
  delete b;
  return 0; 
}

The following code example passes the check and will not give a warning about this issue:

#include <iostream>

class A {
public: 
  A() { }  //OK - contructor does not call any virtual
           //member functions
  virtual void f() const { std::cout << "A::f\n"; }
};

class B: public A {
public:
  virtual void f() const { std::cout << "B::f\n"; }
};

int main(void) {
  B *b = new B();
  delete b;
  return 0; 
}