osx man page for mpi_comm_group

MPI_Comm_group(3OpenMPI)												  MPI_Comm_group(3OpenMPI)

NAME
       MPI_Comm_group  - Returns the group associated with a communicator.

SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Comm_group(MPI_Comm comm, MPI_Group *group)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_COMM_GROUP(COMM, GROUP, IERROR)
	    INTEGER   COMM, GROUP, IERROR

C++ Syntax
       #include <mpi.h>
       Group Comm::Get_group() const

INPUT PARAMETER
       comm	 Communicator.

OUTPUT PARAMETERS
       group	 Group in communicator (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION
       If the communicator is an intercommunicator (enables communication between two groups of processes), this function returns the local group.
       To return the remote group, use the MPI_Comm_remote_group function.

ERRORS
       Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
       tions  do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except  for
       I/O  function  errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be
       used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

Open MPI 1.2							  September 2006					  MPI_Comm_group(3OpenMPI)