Problem Blocking operator=

[Mike - EMAIL IGNORED]

I wrote:

class Parent
{
...
private:
virtual Parent& operator=(const Parent& parent);
};

class Child : public Parent
{
...
private:
virtual Child& operator=(const Child& parent);
};

In neither case was the operator=() defined.

With gcc 3.2, this failed to link, with undefined references
for both operator=(), notwithstanding that it was used nowhere
in my code.

The problem was corrected by removing both "virtual".
Is this expected, or is it a problem with the compiler?

Can anyone cite chapter & verse?

Thanks,
Mike.

 

[Victor Bazarov]

I wrote:

class Parent
{
...
private:
virtual Parent& operator=(const Parent& parent);
};

class Child : public Parent
{
...
private:
virtual Child& operator=(const Child& parent);
};

In neither case was the operator=() defined.

With gcc 3.2, this failed to link, with undefined references
for both operator=(), notwithstanding that it was used nowhere
in my code.

The problem was corrected by removing both "virtual".
Is this expected, or is it a problem with the compiler?

Can anyone cite chapter & verse?

10.3/8: A virtual function declared in a class shall be defined,
or declared pure (10.4) in that class, or both; [...]

Victor

 

[David White]

I wrote:

class Parent
{
...
private:
virtual Parent& operator=(const Parent& parent);
};

class Child : public Parent
{
...
private:
virtual Child& operator=(const Child& parent);
};

In neither case was the operator=() defined.

With gcc 3.2, this failed to link, with undefined references
for both operator=(), notwithstanding that it was used nowhere
in my code.

I think that's normal for virtual functions. By definition, the call of a
virtual function is decided at run-time, so I suppose the easiest
implementation is to make sure they are there, just in case.

The problem was corrected by removing both "virtual".
Is this expected, or is it a problem with the compiler?

'virtual' is inappropriate anyway because the argument type is different in
each case. Typically, assignment operators are not virtual.

DW