Since the buftype need not be constructed out of etype (only type
signatures must match), the holes in etype that may correspond to
file-format-extents should not matter for buftype.
Being able to use MPI_Type_struct is a requirement, in my opinion.
On a different note, I think users will be confused about the word
"displacement," because we are using it to refer to
datatype-displacements as well as the initial displacement in the file
view. I suggest that we rename "file displacement" to something else.
How about "initial-offset" if nothing better?
Rajeev
> Date: Thu, 17 Apr 1997 13:18:16 -0700
> From: johnmay@llnl.gov (John May)
>
> Rajeev Thakur writes:
>
> > If MPI_Type_struct cannot be used to create a filetype in
> > heterogeneous env., how does one specify holes in the file with lb and
> > ub? One may be able to specify lb with MPI_Type_resize (even that's
> > not clear), but what about ub?
>
> I think MPI_Type_resize will do both. You set the lower bound
> explicitly, and the upper bound is implicitly defined by the
> extent you ask for. The rule I suggested says that these
> bounds have to be set on base-type increments. Am I missing
> your point?
>
> > Secondly, if my data structure in memory is an array of structures (in
> > C), how do I write it to the file?
>
> Beats me. Maybe we need to resurrect one of the struct constructors
> that got moved to the JOD?
>
> John