[mpich-discuss] Funky MPI_File_write_at Parameters

[Ellis H. Wilson III]

On 04/12/11 09:54, William Gropp wrote:
> The offset is likely 8 bytes, not 4 (it depends on the MPI
> implementation and file system environment), and the write buffer must
> be non-null unless a datatype with an absolute address is used.  My
> guess is that the offset is 8 bytes, and that is throwing off the
> interpretation of the traceback.

Thanks a lot for your suggestion William.  Ironically I was reading your
book (Using MPI, second edition) to try and figure this out this past
weekend.

I am using MPICH 1.0.7 and PVFS2 2.7.1.  I think the crux of the problem
is in IOR, as it stores offset and count as long long int which is 8
bytes instead of MPICH's expected 4.

I'll investigate, thanks for your help!

ellis