[Mpi3-tools] Type sizes in MPI_T

Martin Schulz schulzm at llnl.gov
Thu Jun 23 21:39:49 CDT 2011

Hi all,

Christof has been going over the MPI_T document (thanks!) and 
found a few issues - I will fix those and post a new draft tonight.

One issue, however, we were not sure about: since we are
not allowing any MPI calls between MPI_T_Init_thread and
MPI_Init (only MPI_T calls), we also cannot call any MPI
Type related calls, such as MPI_Type_size or calls for
naming or setting attributes. The latter we can probably
get away with not having until MPI_Init, but we were not sure
on MPI_Type_size.

Since we are only using basic types, can we assume that they
always represent their corresponding C types as specified in
Section 3.2.2? I always assumed this, but looking closer, we
were not 100% certain on how to interpret the following sentence 
in that section:

Possible values for this argument for C and the corresponding 
C types are listed in Table 3.2.

Does the possible only refer to the values or also to the 
corresponding C types? If it is the former, then we can get
the size simply by calling sizeof(...) and  this is not an



Martin Schulz, schulzm at llnl.gov, http://people.llnl.gov/schulzm
CASC @ Lawrence Livermore National Laboratory, Livermore, USA

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