Re: [boost] Boost.Process 0.5 released

Subject: Re: [boost] Boost.Process 0.5 released
From: Oliver Kowalke (oliver.kowalke_at_[hidden])
Date: 2012-08-19 17:06:07

Am 19.08.2012 18:54, schrieb Boris Schaeling:
> On Sun, 19 Aug 2012 12:46:12 +0200, Klaim - Joël Lamotte 
> <mjklaim_at_[hidden]> wrote:
>
>> [...]Also as pointed by others, it goes agains RAII based design to 
>> force the
>> user to explicitely release resources.
>
> I don't think of the child class has a RAII type (but I see how this 
> made you propose a non-copyable class). It could be a RAII type on 
> Windows as the process and thread handles (which are member variables 
> of the class) have to be closed. But it wouldn't work on POSIX as you 
> have to clean up differently. So I treat the child class as a 
> value-based type which works on Windows and POSIX. I'd also prefer a 
> guaranteed cleanup. But it's not clear how to do this with a RAII type 
> on POSIX (unless you have an idea? :).

I would expect from 'modern' C++ that RAII is heavily used - and a 
process is a system resource. I would find it a little bit odd if a 
process is value-base. What happened if I copy a child class and 
invalidate one of the copies.

I suggest to make the process moveable-only. The default ctor represents 
an 'invalid' process class - testable by child::operator 
<unspecified_bool >() and child::operator!().
child::discard() could move-away the internal representation so that the 
child instance becomes 'invalid' after this function.

Oliver