[Mpi-22] Ticket #46: Add const Keyword to the Cbindings-implementation

[Jeff Squyres]

Can someone explain what the rush is to do this for 2.2?

Is there a problem with putting this issue off until 3.0?

On Mar 18, 2009, at 9:15 PM, Darius Buntinas wrote:

>
> I just want to point out that casting away the const for low-level
> interfaces is really a non issue.  Putting a const on the send buffer
> parameter in an MPI function prototype indicates a contract with the
> user that the MPI implementation will not change the contents of the
> buffer referenced from that function.  As long as the MPI implementor
> knows that a routine called by the library will not modify the buffer
> it's OK to cast away the const.  E.g., the POSIX standard tells you  
> that
> writev must not change the contents of the buffer, so casting away  
> const
> is fine.
>
> Sure, that means that the MPI implementor has to be more careful when
> casting away const to ensure that the function being called won't  
> modify
> the buffer.   But the whole point of the proposal is so that the
> _MPI_user_ doesn't need to do this and instead can count on the  
> compiler
> to do the check.
>
> -d
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-- 
Jeff Squyres
Cisco Systems