I have an application in which various processes create different
amounts of data (including no data at all).
I have found that MPI_Scatterv and MPI_Gatherv do work with arrays
sendcounts or receivecounts containing zeros.
Since i didn't find the case of 0 sizes in the descriptions
of these functions in the MPI reference, i wondered whether
the use of zeroes is legal or if i was simply lucky that it worked.
An other point: currently i use 1-sized buffers in the
case of a 0-sized data transfer.
Now if 0-sized data transfer is legal, would it be ok to
pass NULL for the buffer?