[MPIWG Fortran] Proposal: MPI_SIZEOF not profiled

N.M. Maclaren nmm1 at cam.ac.uk
Fri May 16 09:42:27 CDT 2014

On May 16 2014, Bill Long wrote:
>> From my viewpoint, yes.  MPI_Sizeof has never been an ordinary Fortran
>> function.  I don't know the latest polymorphic features well enough
>> to know whether it even CAN be implemented within the standard.  Indeed,
>> one reasonable way to implement it is by the mpif90 command running a
>> preprocessor on the source to replace it by the relevant value!
> The MPI subroutine MPI_SIZEOF is restricted to arguments of intrinsic 
> numeric type (integer, real, complex). No derived types or polymorphic 
> arguments. Fortran does have an intrinsic, STORAGE_SIZE, that returns the 
> size value in bits. Divide by 8 to get the answer for MPI_SIZEOF. ...

Only since Fortran 2008 (2011) and MPI_Sizeof is a lot older than that.
I don't know how many compilers currently support STORAGE_SIZE, but I
will bet that it is not all, even now.

Nick Maclaren.

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