LANG.FUNCS.SOMF : Symmetrical Operator Member Function

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CodeSonar^® 9.2p0

CONFIDENTIAL

CodeSecure Inc

LANG.FUNCS.SOMF : Symmetrical Operator Member Function

Summary

Properties

Example

class Bad {
public:
    Bad(int x = 0) : i(x) {}
    int get(void) const { return i; }
    Bad operator +(const Bad &o)  const // "Symmetrical Operator Member Function" warning issued here
    {
        return Bad(i + o.i);
    }
    Bad operator +(int x) const         // "Symmetrical Operator Member Function" warning issued here
    {
        return Bad(i + x);
    }
    Bad & operator +=(const Bad &o)     // Not symmetrical; rule does not apply
    {
        i += o.i;
        return *this;
    }
private:
    int i;    
};

Bad operator *(const Bad l, const Bad r)        // OK : not member
{
    return Bad(l.get() * r.get());
}

class Good {
public:
    Good(int x = 0) : i(x) {}
    int get(void) const { return i; }
    friend Good operator+(const Good &l, const Good &r);// OK : friend
    friend Good operator+(const Good &l, int r)         // OK : hidden friend
    {
        return Good(l.i + r);
    }
private:
    int i;
};

Good operator +(const Good &l, const Good &r)
{
    return Good(l.i + r.i);
}

Good operator *(const Good l, const Good r)     // OK : not member
{
    return Good(l.get() * r.get());
}

void symmetrical_operator_member_function(void)
{
    Bad b1(21);
    Bad b2(b1 + 1);
    Bad b3(b1 + b2);
    Good g1(21);
    Good g2(g1 + 1);

    //(void)(1 + b1);   // Would fail to compile
    (void)(b1 * 4);
    (void)(4 * b2);
    b3 += 2;
    (void)(1 + g1);     // Compiles just fine.
    (void)(g1 * 4);
    (void)(4 * g2);
}

Relevant Configuration File Parameters

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