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I notice an uninitialized MPI_Status object can make MPI_Get_count return a wrong result,<br>
when the data amount in the MPI operation is zero (although I only checked MPI-IO).<br>
Attached is a test program that uses MPI collective read where only root process has<br>
non-zero length data to read. The expected result from MPI_Get_count is 0 for all<br>
non-root process. To mimic an uninitialized MPI_Status object, I call memset to make<br>
the object non-zero.<br>
<br>
Here is the code fragment.<br>
<br>
if (rank == 0) len = 10;<br>
else len = 0;<br>
<br>
MPI_File_read_all(fh, buf, len, MPI_BYTE, &status);<br>
<br>
MPI_Get_count(&status, MPI_BYTE, &get_size);<br>
<br>
For process rank > 0, get_size may not be 0.<br>
<br>
<br>
Wei-keng<br>
<br>
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