Re: [boost] Boost.Process 0.5: Another update/potential candidate for an official library

Subject: Re: [boost] Boost.Process 0.5: Another update/potential candidate for an official library
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2012-11-13 17:17:08

Le 13/11/12 22:39, Boris Schaeling a écrit :
> On Thu, 08 Nov 2012 01:08:21 +0100, Alexander Lamaison 
> <awl03_at_[hidden]> wrote:
>
>> [...]Does this mean child *is* copyable on other platforms?  So the 
>> class has
>> entirely different semantics on different platforms?
>
> Yes. It doesn't own resources on POSIX.
>
> I understand what you hint at. I'm not sure though whether we can 
> justify making child non-copyable for POSIX developers just because 
> Windows developers can't copy it.
Uniformity is better. The native_handle could be copyable and this could 
be platform specific. This make evident that the code is platform 
specific as the type is platform specific.

Maybe you could also provide a child::id class that is copyable as e.g. 
std/boost::thread does.
>
>> [...]I still don't get why you're letting this behaviour vary between
>> platform.  Sure, the underlying system calls have different defaults but
>> they are both capable of both behaviours.  The whole point of a
>> platform-independent library is to align such variation.
>
> If you use inherit_env(), you get the cross-platform behavior you are 
> looking for. But I prefer not to break the "pay for what you 
> use"-principle if you don't use inherit_env(). Besides, standardizing 
> the default behavior requires you to pick one. But whether this should 
> be always POSIX, always Windows, always the most convenient or always 
> the easiest to implement - I'm afraid there will be always others who 
> want another default behavior.
>
One alternative is to make it inherit by default, so that a common 
behavior is ensured. Then you can provide a platform specific 
constructor on the platform allowing to don't inherit the environment.

Best,
Vicente