Re: [boost] [process] A doubt about private constructors

From: Jeff Garland (jeff_at_[hidden])
Date: 2006-08-24 10:54:58

Julio M. Merino Vidal wrote:
> Hello everybody,
> 
> At the moment, some objects in the preliminary Boost.Process library
> are only constructed internally by the library.  Examples of these
> include 'status' instances, created by calls to 'child::wait', and
> instances of 'child', created by 'launcher::start'.  This is currently
> done by declaring friendship among the related classes (well, not
> exactly, but almost).
> 
> I believe this is suboptimal because it prevents extensibility.
> Consider a user that wants to create his own Launcher implementation.

What would be the motivation for providing this?

> His code is required to return a new 'child' object.  But, oh!  He
> cannot currently create it because the constructor is private and his
> launcher class is not a friend of the provided 'child'.  Of course, he
> could implement his own 'child' -- and in turn implement his own
> 'status'.  Ouch.
 >
 >...snip details...
 >
> I'm open to other suggestions.

I guess my thought is that if you want extensibility, just make the 
constructors public and move on.  That's the cleanest and easiest way...

HTH,

Jeff