/*D
   MPI_Comm_rank - Determines the rank of the calling process in the communicator

Synopsis:
.vb
int MPI_Comm_rank(MPI_Comm comm, int *rank)
.ve

Input Parameters:
. comm - communicator (handle)

Output Parameters:
. rank - rank of the calling process in group of comm (integer)

.N ThreadSafe

.N Fortran

.N Errors
.N MPI_SUCCESS
.N MPI_ERR_ARG
.N MPI_ERR_COMM
.N MPI_ERR_OTHER

D*/

