Dear all, It is not clear to me if I am allowed to make calls to MPI_Is_thread_main from any thread if I initialized MPI with the MPI_THREAD_FUNNELED mode. For this mode, the norm says: "the application must ensure that only the main thread makes MPI calls" (page 384, lines 46-47) Therefore, a call to MPI_Is_thread_main should be incorrect. But in this case, how can I determine which thread is the main one? Or, maybe, some MPI calls could be explicitly allowed to be made by any thread? Best regards, Philippe Wautelet -------------------------------------------------------------------- Philippe Wautelet (Research Engineer) [email protected] Tel. : 01 69 35 85 76 Fax : 01 69 85 37 75 IDRIS, Batiment 506, BP 167, 91403 ORSAY Cedex, France Prof. website : http://www.idris.fr Private website : http://www.fractalzone.be --------------------------------------------------------------------