NAME

       MPI_Comm_get_parent -  Return the parent communicator for this process

SYNOPSIS

       int MPI_Comm_get_parent(MPI_Comm * parent)

OUTPUT PARAMETERS

       parent - the parent communicator (handle)

NOTES

       If a process was started with MPI_Comm_spawn or MPI_Comm_spawn_multiple , MPI_Comm_get_parent returns the
       parent  intercommunicator  of  the  current  process. This parent intercommunicator is created implicitly
       inside of MPI_Init and is the same intercommunicator returned by MPI_Comm_spawn in the parents.

       If the process was not spawned, MPI_Comm_get_parent returns MPI_COMM_NULL .

       After the parent communicator is freed or disconnected, MPI_Comm_get_parent returns MPI_COMM_NULL .

THREAD AND INTERRUPT SAFETY

       This routine is both thread- and interrupt-safe.  This means that this routine  may  safely  be  used  by
       multiple threads and from within a signal handler.

NOTES FOR FORTRAN

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

ERRORS

       All  MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the
       function and Fortran routines in the last argument.  Before the value is returned, the current MPI  error
       handler  is called.  By default, this error handler aborts the MPI job.  The error handler may be changed
       with   MPI_Comm_set_errhandler   (for   communicators),   MPI_File_set_errhandler   (for   files),    and
       MPI_Win_set_errhandler  (for  RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its use
       is deprecated.  The predefined error handler MPI_ERRORS_RETURN may be used to cause error  values  to  be
       returned.   Note that MPI does not guarentee that an MPI program can continue past an error; however, MPI
       implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identified  by  a  specific  error  class
              (e.g., MPI_ERR_RANK ).

                                                   11/12/2019                             MPI_Comm_get_parent(3)