From: Erez Haba <erezh@XXXXXXXXXXXXX>
Date: January 18, 2008 7:00:55 PM CST
To: "mpi-21@mpi-forum.org" <mpi-21@XXXXXXXXXXXXX>
Subject: RE: [mpi-21] const MPI C++ handles
Reply-To: mpi-21@XXXXXXXXXXXXX

> Just trying to be cautious: would there ever be a reason to have a  
> non-
> const version of the Set_* functions?

Yes, if the impl caches info in its own objects and change it when  
the Set_* function is called. (but then it can use the mutable  
keyword :))

Thanks,
.Erez

-----Original Message-----
From: owner-mpi-21@XXXXXXXXXXXXX
On Behalf Of Jeff Squyres
Sent: Friday, January 18, 2008 11:19 AM
To: mpi-21@XXXXXXXXXXXXX
Subject: Re: [mpi-21] const MPI C++ handles

On Jan 18, 2008, at 2:11 PM, Erez Haba wrote:

> I looked up this issue and did not find a C++ *standard* that spans
> that many platforms and compilers.
>
> The ISO C++ 98 standard itself does have libraries, but they provide
> the headers which are less ambiguous. (including various const
> values (like INT_MAX)) (think ABI :))

Hah!  Surely you're not implying that C++ compilers produce code that
is ABI-compatible with other C++ compilers?  :-D

> I agree that we'll need to enable the recommendation in the standard
> interface. We'll need to agree that the semantic of changing the
> underlying MPI handle is not changing the object (and thus can
> define the method as const).
>
> I don't think you'll need an overloaded function for the Set_*
> functions; const methods are good for non const objects.

Good point -- a const method will match a corresponding non-const
(*this).

Just trying to be cautious: would there ever be a reason to have a non-
const version of the Set_* functions?

--
Jeff Squyres
Cisco Systems