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 issue. Thanks, Martin ________________________________________________________________________ Martin Schulz, [email protected], http://people.llnl.gov/schulzm CASC @ Lawrence Livermore National Laboratory, Livermore, USA