Hi Junchao, This is a recent item we added to the errata. I don't believe it has been merged into the online errata yet. The text for the errata is: page 568, line 31 add: Any output parameter to MPI_T_cvar_get_info can have a NULL value. In this case, the implementation will ignore the parameter and not return a value for that parameter. page 576, line 46 add: Any output parameter to MPI_T_pvar_get_info can have a NULL value. In this case, the implementation will ignore the parameter and not return a value for that parameter. page 586, line 22 add: Any output parameter to MPI_T_category_get_info can have a NULL value. In this case, the implementation will ignore the parameter and not return a value for that parameter. You can see the evolution of this change here: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/378 Kathryn On Sep 23, 2013, at 4:03 PM, Junchao Zhang <[email protected]<mailto:[email protected]>> wrote: Hello, For function "int MPI_T_pvar_get_info(int pvar_index, char *name, int *name_len, int *verbosity, int *var_class, ...)", MPI_T defines semantics when name or name_len are NULL. But for other args, if they are NULL, is it a user program error or should we just ignore it? I prefer the latter. But the standard doesn't say it. Thanks --Junchao Zhang _______________________________________________ mpiwg-tools mailing list [email protected]<mailto:[email protected]> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools ______________________________________________________________ Kathryn Mohror, [email protected]<mailto:[email protected]>, http://people.llnl.gov/mohror1 CASC @ Lawrence Livermore National Laboratory, Livermore, CA, USA