[Ns-developers] CreateObject and non-default constructors

[Nicola Baldo]

Hi Mathieu,

Mathieu Lacage wrote:
> hi,
> 
> Recently, someone pointed out to me privately that we poorly support
> calling non-default constructors with CreateObject. In fact, we don't
> support it. I will skip over the lengthy discussion of how we ended up
> where we are today, and, instead, will get to what we could do to
> support this: 2 options (patches attached).
> 
> 1. compatible option (a.patch)
> 2. less compatible option (b.patch)
> 
> 1) compatible option: introduce CreateObjectNoAttributes: 
> 
> template <typename T>
> Ptr<T> CreateObjectNoAttributes (void);
> 
> template <typename T, typename T1>
> Ptr<T> CreateObjectNoAttributes (T1 a1);
> 
> template <typename T, typename T1, typename T2>
> Ptr<T> CreateObjectNoAttributes (T1 a1, T2 a2);
> 
> ...
> 
> It's not very pretty for something which appears to be regularly
> complained about by users.
> 
> 2) less compatible option: modify CreateObject, introduce
> CreateObjectWithAttributes
> 
> Despite not being fully compatible with existing code, I expect the
> fallout on users to be minimal because, frankly, no one calls
> CreateObject<> with construction-time attributes so, almost no one will
> notice this change.


I prefer the second alternative, because it makes the use of non-default 
constructors for Object similar to that of RefCountBase.

Nicola