[mpi-21] const C++ MPI handles (take 2)

Jeff Squyres jsquyres at [hidden]
Fri Jan 18 13:13:33 CST 2008

On Jan 18, 2008, at 2:02 PM, Erez Haba wrote:

> Okay; about one issue at a time.

Changing mail subject to reflect the discussion...

> *For this sentence* it does not matter what's a common usage for C++  
> global variables. Some MPI implementations would need to have non- 
> const qualified global objects.

Why?  As I understand it, most (all?) MPI C++ implementations  
currently only require some objects to be non-const because of the  
standard-related issue that was already raised (Set_attr(),  
Set_name(), Set_errhandler() methods not having const variants).  Is  
there a reason that an implementation would *need* MPI handles to be  

Per my prior mail, I believe that the standard should specify that  
some of the methods on these classes should have const and non-const  
variants, and then it should be fine to require that the predefined  
handles be const.

So the question is still open: what's common practice in the C++  
community regarding const/non-const global variable specification?   
This question will be moot if you can demonstrate that an  
implementation would need non-const C++ MPI predefined handles.

Jeff Squyres
Cisco Systems

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