Hello, I noticed a difference in the type used to declare pids in two different areas, and I'm curious: 1) Why aren't they the same type? 2) Why aren't we using a standardzed type like pid_t ? Location 1) http://www.mcs.anl.gov/research/projects/mpi/mpi-debug/ Taken from: mpich/mpid/ch2/attach.h typedef struct { char * host_name; /* Something we can pass to inet_addr */ char * executable_name; /* The name of the image */ int pid; /* The pid of the process */ } MPIR_PROCDESC; Location 2) http://www.mcs.anl.gov/research/projects/mpi/mpi-debug/mpi_interface.h.html Taken from: mpich/src/infoexport/mpi_interface.h #if (FOR_MPI2) /* For handling attachment to new processes in MPI-2 we need to know * where they are. */ typedef struct mqs_process_location { long pid; char image_name [FILENAME_MAX]; char host_name [64]; } mqs_process_location; #endif These two structures look to have similar purposes. Is one a "newer" version of the other? Are they from different MPI implementations of the MSQ? Thanks, Geoff Paulsen