[MPI3 Fortran] Default integers open for discussion

[Craig Rasmussen]

On Sep 2, 2009, at 9:23 AM, Lionel, Steve wrote:

>
> As I have stated earlier, it would be a big mistake to rely on  
> default integer (or other) kinds.  The declarations need to specify  
> the kind and this should be based on named constants in the MPI3  
> module which take values from those in ISO_C_BINDING (C_INT).  The  
> programmer would be encouraged to use the MPI kind values but not  
> required to do so unless the default kind in their environment is a  
> mismatch for what MPI is expecting.
>

I've been back and forth on this (as well as a few others I think).   
I'm currently leaning toward using default integers.  Primarily  
because to do otherwise could potentially break countless lines of  
users code.  I don't want to be in the line of fire when this happens.

Although, perhaps the vendors could easily take care of this with a  
configure option.  They can use default kinds as an option for the  
names constant kinds in MPI3.  Another option would be to provide the  
"best" values for integer kinds.  A user would be able to write code  
to adhere to the standard (using named kinds), but would not be  
required to do so.

My guess would be that all installations would go ahead and configure  
for default kinds.

-craig