Pimpl copying

[Peter Kümmel]

Clarence Dang wrote:
> On Friday 14 July 2006 17:13, Peter Kümmel wrote:
>> Clarence Dang wrote:
>>> On Friday 14 July 2006 07:05, Peter Kümmel wrote:
>>>> +KTempDir& KTempDir::operator=(const KTempDir& rhs)
>>>> +{
>>> BTW, in general (but not this case), you need:
>>>
>>> if (this == &rhs)
>>> 	return *this;
>> But I don't understand why not in this case?
> 
> class KTempDir::Private
> {
> public:
>    int _error;
>    QString _tmpName;
>    bool _exists;
>    bool _autoDelete;
> };
> 
> In this case, if this == &rhs, you would be assigning int's, QString's and 
> bool's to themselves - fairly harmless.  But just imagine code like this:
> 
> kpPenBrush &kpPenBrush::operator= (const kpPenBrush &rhs) const
> {
>     d->ref--;
>     if (d->ref == 0)
>         delete d;  <-- danger
> 
>     d = rhs.d;  <-- if this == &rhs, rhs.d may have been deleted!
>     d->ref++;
> }
> 
> 

I see, it was not wrong only harmless.