debian man page for mpi_comm_rank

MPI_Comm_rank(3)							MPI							  MPI_Comm_rank(3)

NAME
       MPI_Comm_rank -	Determines the rank of the calling process in the communicator

SYNOPSIS
       int MPI_Comm_rank( MPI_Comm comm, int *rank )

INPUT ARGUMENT
       comm   - communicator (handle)

OUTPUT ARGUMENT
       rank   - rank of the calling process in the group of comm (integer)

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_COMM
	      - Invalid communicator.  A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank ).

LOCATION
       comm_rank.c

								     7/28/2010							  MPI_Comm_rank(3)