[mpi-22] FW: [mpi-21] Proposal: MPI_OFFSET built-in type

[Rajeev Thakur]

Is it an interface change? It would be an addition to the set of predefined
types, such as MPI_INT, MPI_CHAR, so it should just work I think.

>> MPI Datatype: MPI_OFFSET
>> Corresponding C type: long long int
>> Corresponding Fortran type: INTEGER(KIND=MPI_OFFSET_KIND) 

The corresponding C type should be "implementation defined". It could be int
for example in an implementation that only supports 32-bit file sizes.

Rajeev

> -----Original Message-----
> From: mpi-22-bounces_at_[hidden] 
> [mailto:mpi-22-bounces_at_[hidden]] On Behalf Of Richard Graham
> Sent: Thursday, January 24, 2008 11:48 AM
> To: mpi-22_at_[hidden]
> Subject: Re: [mpi-22] FW: [mpi-21] Proposal: MPI_OFFSET built-in type
> 
> Do you think this should go into 2.2 or 3.0 ?  I ask not 
> because the change
> is large, but because it will change the signature of several 
> interface
> functions (presumably marking the older functions as deprecated - for
> removal in X number of years).  There is another change that 
> I would like to
> see added to the standard, which is adding a way to convey information
> between MPI_Alloc_mem() to the functions using this memory, 
> w/o forcing the
> implementations to try and use all sorts of non-portable 
> solutions to figure
> out if this memory can be used "as-is" by the network layer, 
> of if it needs
> to be "prepared" (pinned, and ?).
> 
> It seems prudent to combine such interface changes into the 
> smallest number
> of changes (1 is preferred).
> 
> What do you think ?
> Rich
> 
> 
> On 1/24/08 12:18 PM, "Rajeev Thakur" <thakur_at_[hidden]> wrote:
> 
> > A similar one is needed for MPI_Aint.
> > 
> > Rajeev 
> > 
> >> -----Original Message-----
> >> From: mpi-22-bounces_at_[hidden]
> >> [mailto:mpi-22-bounces_at_[hidden]] On Behalf Of Richard Graham
> >> Sent: Thursday, January 24, 2008 11:09 AM
> >> To: mpi-22_at_[hidden]
> >> Subject: [mpi-22] FW: [mpi-21] Proposal: MPI_OFFSET built-in type
> >> 
> >> Moving this to the appropriate list.
> >> 
> >> Rich
> >> 
> >> ------ Forwarded Message
> >> From: Robert Latham <robl_at_[hidden]>
> >> Reply-To: "Mailing list for discussion of MPI 2.1"
> >> <mpi-21_at_[hidden]>
> >> Date: Thu, 24 Jan 2008 10:41:52 -0600
> >> To: <mpi-21_at_[hidden]>
> >> Subject: [mpi-21] Proposal: MPI_OFFSET built-in type
> >> 
> >> I hope this is less contentious than adding 'const' keywords...
> >> 
> >> 
> >> I would like to propose a new built-in type MPI_OFFSET, 
> defined to be
> >> a type corresponding to INTEGER(KIND=MPI_OFFSET_KIND) or MPI_Offset
> >> 
> >> This is a minor addition to the standard, which would have 
> no impact
> >> on existing code while serving to simplify code which 
> exchanges file
> >> offsets among processes.
> >> 
> >> There is a workaround in the standard: a user can define a 
> type from
> >> MPI_BYTE:
> >> 
> >>  MPI_Type_contiguous(sizeof(MPI_Offset), MPI_BYTE, &offtype);
> >> 
> >> However, it would clearly be more convienient to operate 
> on built-in
> >> types.  
> >> 
> >> MPI Datatype: MPI_OFFSET
> >> Corresponding C type: long long int
> >> Corresponding Fortran type: INTEGER(KIND=MPI_OFFSET_KIND)
> >> 
> >> 
> >> Thanks
> >> ==rob
> >> 
> >> -- 
> >> Rob Latham
> >> Mathematics and Computer Science Division    A215 0178 
> EA2D B059 8CDF
> >> Argonne National Lab, IL USA                 B29D F333 
> 664A 4280 315B
> >> _______________________________________________
> >> mpi-21 mailing list
> >> mpi-21_at_[hidden]
> >> http://lists.cs.uiuc.edu/mailman/listinfo/mpi-21
> >> 
> >> ------ End of Forwarded Message
> >> 
> >> _______________________________________________
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> >> mpi-22_at_[hidden]
> >> http://lists.cs.uiuc.edu/mailman/listinfo/mpi-22
> >> 
> >> 
> > 
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