Hi Junchao, The MPI standard says "However, MPI implementations are not allowed to change the index of a performance variable or to delete a variable once it has been added to the set. When a variable becomes inactive, e.g., through dynamic unloading, accessing its value should return a corresponding error code." Does it imply, 1) MPI_T_pvar_get_num() will return a N that counts both active and inactive pvars Yes. 2) MPI_T_pvar_get_info(par_index, ...,) may return MPI_T_ERR_INVALID_INDEX even for a par_index < N Yes. 3) When a pvar is re-activated, it keeps its old index? Yes. These are not obvious in the standard. Thanks for your feedback. We have updated the example for control variables (Example 14.4) to illustrate your first point (will be part of the next released standard). However, I realize now that we should do the same for other examples in the chapter. We possibly need to add some text to address this as well, maybe as errata since it seems clarification could help avoid confusion. I'll bring this up in the working group. Kathryn 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